Plant Science

BackgroundDark-induced senescence (DIS) is a widely used model for dissecting the regulatory mechanisms that manage leaf aging, redox imbalance, and cell death (CD) in plants. Salicylic acid (SA) is a central hormonal regulator of these processes. However, the mechanism involving upstream components, which integrate SA-dependent pathways with antioxidant homeostasis during DIS, remains unresolved. CYSTEINE-RICH RECEPTOR-LIKE KINASE 5 (CRK5) is a membrane-localized protein that plays a role in developmental and stress-responsive pathways. Its promoter contains multiple W-box cis-elements, indicating regulation by WRKY factors in SA-mediated pathways. This study investigates how CRK5 modulates SA-dependent CD and antioxidant dynamics during DIS. ResultsIn this study, SA-accumulating mutant crk5 exhibited accelerated senescence, elevated electrolyte leakage, enhanced micro-lesion formation, and markedly increased reactive oxygen species (ROS) accumulation under both control and dark conditions. These phenotypes were accompanied by a substantial reduction in carotenoid and xanthophyll pools, enhanced accumulation of phenolic compounds, and increased free radical scavenging capacity, including ascorbate peroxidase, catalase, and superoxide dismutase activities. Importantly, crk5 phenotype was fully reverted in crk5sid2 and crk5NahG double mutants, confirming that crk5 DIS phenotype is induced by activation of the SA-signaling pathway. Transcriptome profiling revealed extensive deregulation of senescence-, CD-, and redox-associated genes in crk5 during darkness, including strong induction of SAGs, metacaspases, autophagy, and antioxidant-related transcripts. The line with constitutively enhanced SA level (cpr1), used as a control, showed similar phenotypes to crk5, although transcriptional reprogramming was largely absent in cpr1 after darkness, highlighting CRK5 as a key upstream negative regulator of SA-mediated CD and positive regulator of antioxidant homeostasis. ConclusionOur work presents CRK5 as a central regulatory hub that inhibits the SA-signaling, ROS burst, and CD activation during DIS. Loss of CRK5 function is associated with the activation of SA-signaling, altered antioxidant systems, increased ROS burden, and ROS-driven CD acceleration, resulting in accelerated senescence. Conversely, suppression of SA-biosynthesis or -catabolism in a crk5 background restores the wild-type phenotype. These findings position this receptor kinase as a key mediator that coordinates hormonal, metabolic, and oxidative pathways to maintain leaf viability, providing mechanistic insight into the control of stress-induced senescence and CD in Arabidopsis.

Enzymatic browning significantly affects the appearance and quality of fresh-cut fruit. Light treatment can effectively inhibit fresh-cut apple browning via unknown molecular mechanisms. Here, we found that the application of purple LED light decreased the browning index of fresh-cut apple, delaying browning as compared to that of fresh-cut apple placed in the dark, and suggesting that purple LED light suppresses browning. In addition, the expression levels of MdHY5 and MdHY5S, important BASIC LEUCINE ZIPPER DOMAIN (bZIP) transcription factors that are involved in the light signaling pathway, were increased by purple LED light treatment. Silencing MdHY5 and MdHY5S in apple meant that purple LED light treatment no longer inhibited fresh-cut apple browning, the expression levels of the browning-related genes POLYPHENOL OXIDASE (MdPPO) and PEROXIDASE (MdPOD) increased, and the expression of the phenolic synthesis gene PHENYLALANINE AMMONIALYASE (MdPAL) decreased. Further study revealed that MdHY5 and MdHY5S bind to the MdPPO and MdPOD promoters, reducing their transcription. In contrast, MdHY5 and MdHY5S bind to the MdPAL promoter, enhancing transcription. Further research revealed that MdHY5 and MdHY5S also bind directly to each others promoters to form a positive transcriptional loop that activates their transcription. Our findings revealed that purple LED light inhibits browning and increases phenolics synthesis in fresh-cut apple by activating MdHY5 and MdHY5S. The results provide a theoretical basis upon which the new methods for improving the appearance and quality of fresh-cut apple can be based.

Proline is a key compound that lowers cell water potential, scavenges reactive oxygen species, and stabilizes biomolecules and cell membranes, thus reducing stress-induced damage. Proline dehydrogenase (ProDH), the first rate-limiting enzyme in proline degradation, plays a crucial role in proline accumulation. We explored the role of the GhProDH gene family in regulating physiological responses to stress conditions through transcriptome, metabolome and functional analyses. Overexpression and gene silencing lines in Arabidopsis and cotton revealed that GhProDH2 plays a key role in regulating cottons tolerance to drought and salt stress. GhProDH2-4 improves cottons tolerance to drought and salt stress by engaging in carbon metabolism, glyoxylate cycle, and flavonoid metabolism pathways. These findings highlight the potential role of GhProDH2-4 to improve cotton stress resistance by genetically modifying pathways involved in proline biosynthesis and degradation.

The role of the cytosolic O-acetylserine-(thiol) lyase A (OASTLA), chloroplastic OASTLB and mitochondrion OASTLC in plant resistance/sensitivity to selenate was studied in Arabidopsis plants. Impairment in OASTLA and B resulted in reduced biomass, chlorophyll and soluble protein levels compared with impaired OASTL C and Wild-Type treated with selenate. The lower organic-Se and protein-Se levels followed by decreased organic-S, S in proteins and total glutathione in oastlA and oastlB compared to Wild-Type and oastlC are indicative that Se accumulation is not the main cause for the stress symptoms, but rather the interference of Se with the S-reduction pathway. The increase in sulfite oxidase, adenosine 5'-phosphosulfate reductase, sulfite reductase and OASTL activity levels, followed by enhanced sulfite and sulfide, indicate a futile anabolic S-starvation response to selenate-induced organic-S catabolism in oastlA and oastlB compared to Wild-Type and oastlC. Additionally, the catabolic pathway of L-cysteine degradation was enhanced by selenate, and similar to L-cysteine producing activity, oastlA and B exhibited a significant decrease in L-cysteine desulfhydrase (DES) activity, compared with WT, indicating a major role of OASTLs in L-cysteine degradation. This notion was further evidenced by sulfide dependent DES in-gel activity, immunoblotting, immunoprecipitation with specific antibodies and identification of unique peptides in activity bands generated by OASTLA, B and C. Similar responses of the OASTLs in Seleno-Cysteine degradation was demonstrated in selenate stressed plants. Notably, no L-cysteine and L-Seleno-Cysteine DES activity bands but those related to OASTLs were evident. These results indicate the significance of OASTLs in degrading L-cysteine and L-SelenoCysteine in Arabidopsis. SummaryThe cytosolic OASTLA and chloroplastic OASTLB have significantly higher desulfhydrase activity rates than the cytosolic DES1 and are able to degrade L-Cys and L-SeCys to sulfide and selenide, respectively in Arabidopsis.

Among the three active aldehyde oxidases in Arabidopsis thaliana leaves (AAO1-3), AAO3, which catalyzes the oxidation of abscisic-aldehyde to abscisic-acid, was shown recently to function as a reactive aldehyde detoxifier. Notably, aao2KO mutants exhibited less senescence symptoms and lower aldehyde accumulation, such as acrolein, benzaldehyde, and HNE than in wild-type leaves exposed to UV-C or Rose-Bengal. The effect of the absence of AAO2 expression on aldehyde detoxification by AAO3 and/or AAO1 was studied by comparing the response of wild-type plants to the response of aao1Single mutant, aao2KO mutants and single mutants of aao3Ss. Notably, aao3Ss exhibited similar aldehyde accumulation and chlorophyll content to aao2KO treated with UV-C or Rose-Bengal. In contrast, wild-type and aao1S exhibited higher aldehyde accumulation that resulted in lower remaining chlorophyll than in aao2KO leaves, indicating that the absence of active AAO2 enhanced AAO3 detoxification activity in aao2KO mutants. In support of this notion, employing abscisic-aldehyde as a specific substrate marker for AAO3 activity revealed enhanced AAO3 activity in aao2KO and aao3Ss leaves compared to wild-type treated with UV-C or Rose Bengal. The similar abscisic acid level accumulated in leaves of unstressed or stressed genotypes indicates that aldehyde detoxification by AAO3 is the cause for better stress resistance in aao2KO mutants. Employing the sulfuration process (known to activate aldehyde oxidases) in wild-type, aao2KO, and molybdenum-cofactor sulfurase (aba3-1) mutant plants revealed that the active AAO2 in WT employs sulfuration processes essential for AAO3 activity level, resulting in the lower AAO3 activity in WT than AAO3 activity in aao2KO.

Ribonucleotide reductase (RNR), functioning in the de novo synthesis of dNTPs, is crucial for DNA replication and cell cycle progression. However, the knowledge about the RNR in plants is still limited. In this study, we isolated ylc1 (young leaf chlorosis 1) mutant, which exhibited many development defects such as dwarf stature, chlorotic young leaf, and smaller fruits. Map-based cloning, complementation, and knocking-out experiments confirmed that YLC1 encodes a large subunit of RNR (SlRNRL1), an enzyme involved in the de novo biosynthesis of dNTPs. Physiological and transcriptomic analyses indicate that SlRNRL1 plays a crucial role in the regulation of cell cycle, chloroplast biogenesis, and photosynthesis in tomato. In addition, we knocked out SlRNRL2 (a SlRNRL1 homolog) using CRISPR-Cas9 technology in the tomato genome, and found that SlRNRL2, possessing a redundant function with SlRNRL1, played a weak role in the formation of RNR complex due to its low expression intensity. Genetic analysis reveals that SlRNRL1 and SlRNRL2 are essential for tomato growth and development as the double mutant slrnrl1slrnrl2 is lethal. This also implies that the de novo synthesis of dNTPs is required for seed development in tomato. Overall, our results provide a new insight for understanding the SlRNRL1 and SlRNRL2 functions and the mechanism of de novo biosynthesis of dNTPs in plants.

Glutaredoxins (Grxs) are small, ubiquitous, multi-functional proteins present in different compartments of plant cells. A chloroplast targeted class I GRX (CcGRXS12) gene was isolated from Capsicum chinense during the pepper mild mottle virus (PMMoV) infection. Functional characterization of the gene was performed in N. benthamiana transgenic plants transformed with native C. chinense GRX (Nb:GRX), GRX-fused with GFP (Nb:GRX-GFP) and GRX truncated for the chloroplast targeting sequences but fused with GFP (Nb:{Delta}2MGRX-GFP). Over-expression of CcGRXS12 inhibits the PMMoV-I accumulation at late stage of infection and is accompanied with the activation of SA- pathway pathogenesis related (PR) transcripts, and suppression of JA/ET- pathway transcripts. Further the reduced accumulation of auxin-induced Glutathione-S-Transferase (pCNT103) in CcGRXS12 over expressing lines indicates that the protein could able to protect the plants from the oxidative stress caused by the virus. PMMoV-I infection increases accumulation of pyridine nucleotides (PNs) mainly due to the reduced form of PNs (NAD(P)H) and it was higher in Nb:GRX-GFP lines compared to other lines where infection is limited. Apart from biotic stress, CcGRXS12 protects the plants from abiotic stress conditions caused by H2O2 and herbicide paraquat. CcGRXS12 exhibits GSH-disulphide oxidoreductase activity in vitro however devoid of complementary Fe-S cluster assembly mechanism in yeast.

In the model plant Arabidopsis thaliana, parental age is known to affect somatic mutation rates in their immediate progeny and here we show that this age dependent effect persists across successive generations. Using a set of detector lines carrying the mutated uidA gene, we examined if a particular parental age maintained across five consecutive generations affected the rates of base substitution (BSR), intrachromosomal recombination (ICR), frameshift mutation (FS), and transposition. The frequency of functional GUS reversions were assessed in seedlings as a function of identical/different parental ages across generations. In the context of a fixed parental age, BCR/ICR rates were unaffected in the first three generations, then dropped significantly in the 4th and increased in most instances in the 5th generation. On the other hand, with advancing parental ages, BSR/ICR rates remained high in the first two/three generations, with a striking resemblance in the pattern of mutation rates. We adopted a novel approach of identifying and tagging flowers pollinated on a particular day, thereby avoiding biases due to potential emasculation induced stress responses. Our results suggest a time component in counting the number of generations a plant has passed through self-fertilization at a particular age in determining the somatic mutation rates.

Abscisic acid (ABA) plays a vital role in coordinating physiological processes during fresh fruit ripening. ABA can bind to ABA receptors which interacts and inhibits their co-receptors type 2C phosphatases (PP2Cs). However, the dissected mechanism of PP2C during fruit ripening is unclear. In this study, we identify the role of SlPP2C3, a tomato type 2C phosphatase, as a negative regulator of ABA signaling and fruit ripening. SlPP2C3 selectively interacted with monomeric ABA receptors and SlSnRK2.8 kinase in both yeast and tobacco epidermal cells. Expressions of SlPP2C3 were observed in all tissues, and it negatively correlated with the fruit ripening which was induced by exogenous ABA. Tomato plants with suppressed SlPP2C3 expression exhibited enhanced sensitivity to ABA, while SlPP2C3 over-expressed plants were less sensitive to ABA. Meaningfully, lack of SlPP2C3 expression causes the acceleration of fruit ripening onset via the alternation of ABA signaling activity, and the fruit gloss is affected by the changes of outer epidermis structure. RNA-seq analysis found significant different expression of cuticle-related genes in pericarp between wild-type and SlPP2C3 suppressed lines. Taken together, our finding demonstrate that SlPP2C3 plays an important role in the regulation of fruit ripening and fruit appearance quality in tomato.

DNA methylation plays a crucial role in regulating fruit ripening and seed development. It remains unknown about the dynamic characteristics of DNA methylation and its regulation mechanisms in morpho-physiological dormancy (MPD)-typed seeds with recalcitrant characteristics. The P. notoginseng seeds are defined by the MPD and are characterized by a strong sensitivity to dehydration during the after-ripening process. We performed DNA methylomes, siRNA profiles, and transcriptomes of embryo and endosperm in P. notoginseng seeds at different after-ripening stages. Herein, we find that the CHH hyper-methylation contributes to the global increase in DNA methylation during the after-ripening process of P. notoginseng seeds. The endosperm genome is hyper-methylated compared to the embryo genome. The CHH hyper-methylation is caused by the high expression level of DNA methyltransferase PnCMT2 in the embryo, and PnDRM2 in the endosperm, respectively. The CHH hyper-methylation alters gene transcription levels to regulate the after-ripening and dormancy of recalcitrant seeds. For example, it inhibits the expression of genes in embryo development to make seeds maintain a dormant status, whereas it activates the expression of genes in the hormone-mediated signaling pathway, and energy metabolism to accomplish the MPD-typed seed after-ripening process. Together, our findings reveal a global increase in DNA methylation and its vital driver in gene expression, and thus elucidate how global CHH hyper-methylation regulates the after-ripening in recalcitrant MPD-typed seeds. This work establishes a key role for epigenetics in regulating the dormancy of MPD-typed seeds with recalcitrant characteristics.

ADP-ribosylation mediated by ADP-ribosyltransferases (ARTs) is an intricate modification that regulates diverse cellular processes including DNA repair, chromatin remodeling and gene transcription responding to stresses. In addition to the canonical poly(ADP-ribose) polymerases (PARPs), plant specific SRO (Similar to RCD One) family also contain the catalytic core of the PARP domain. However, whether the PARP domains in SROs execute the ART function is still under debate. In 2014, we reported a wheat SRO, Ta-sro1, had the ADP-ribosyltransferase activity and enhanced wheat seedling growth and abiotic stress resistance, however, a recent work by Vogt et al. showed that Ta-sro1 without ADP-ribosyltransferase activity. Based on the recent progress on PARPs and SROs in relation to ADP-ribosyltransferase activity, along with our former and recent evolving results, we argued that Ta-sro1 is a non-canonical ADP-ribosyltransferase with the enzymatic activity. Although we have revealed the novel mechanism of Ta-sro1 regulate redox homeostasis and enhance salinity stress tolerance through interacting with TaSIP1, it is of interest to further clarify whether and how the enzymatic activity of Ta-sro1 responsible for the salinity tolerance of wheat. Our study raises some interesting points and caveats that helpful for understanding the research progresses and debates about the enzymatic activity of SROs.

The role of sirtuins in plants are slowly unraveling. There are only reports of H3K9Ac deacetylation by OsSRT1. Here our studies shade light on its dual enzyme capability with preference for mono ADP ribosylation over deacetylation. OsSRT1 can specifically transfer the single ADP ribose group on its substrates in an enzymatic manner. This mono ADPr effect is not well known in plants, more so for deacetylases. The products of this reaction (NAM and ADP ribose) have immense negative effect on this enzyme suggesting a tighter regulation. Resveratrol, a natural plant polyphenol proves to be a strong activator of this enzyme at 150 M concentration. Under different abiotic stress conditions, we could link this ADP ribosylase activity to the DNA repair pathway by activating the enzyme PARP1. Metal stress in plants also influences these enzyme activities. HighlightsO_LIOsSRT1 can transfer a single moiety of ADP-ribose on itself as well as other nuclear proteins like histones H3 and H2A. C_LIO_LINAM, ADP-ribose and certain metal ions negatively regulate this ADP-ribose transfer. C_LIO_LIADPr of OsPARP1 and OsPARP2 links OsSRT1 to DNA damage repair pathways. C_LIO_LIOsSRT1 positively regulates the activity of OsPARP1 by ADP ribosylating it. C_LIO_LIOn plants exposure to H2O2 (oxidative stress) and Arsenic toxicity, there is a link between the increased activity of the players of DNA damage repair system and overexpression of OsSRT1. C_LI

Mitogen-activated protein kinases (MAPKs) are important signaling players involved in various responses to diverse environmental stresses. MAP kinase phosphatases (MKPs) are crucial negative regulators of MAPKs and control the intensity and duration of MAPK activation. It has been shown that transgenic tobacco plants with increased glutathione content display an oxidative shift and have constitutively active immunity-related MAPKs. The mechanism by which glutathione can activate or keep these MAPKs in activated state is unclear. In this study, it is shown that the Arabidopsis stress-related MAPKs, AtMPK3 and AtMPK6 are hypersensitive to a pathogen-associated molecular pattern flg22 in the cat2-1 line, under the conditions causing an altered glutathione homeostasis and elevated oxidative stress responses in this background. As AtMKP2 is the only dual specificity phosphatase deactivating AtMPK3 and AtMPK6 in response to oxidative stress, the stability of the wild-type AtMKP2 protein and the mutant version of the protein with the substitution of the cys109 in the active site with serine has been studied in wild type (Col-0) and cat2-1 background. The results indicate that AtMKP2 is a stable protein in both genetic backgrounds, whereas the active site cys109 stabilizes the protein under severe oxidative stress conditions and can be glutathionylated in vitro.

The ribosomal protein SA plays an essential role in multiple aspects and is involved in plant growth and response to various stresses. Drought threatens pepper yield and quality. However, the resistance mechanism of pepper in response to drought are complex and not yet fully understood. Here, we describe the role of CaSLP in mediating pepper tolerance to drought stress. we found that CaSLP was highly expressed under drought and salicylic acid (SA) stress, and CaSLP was localized in cell nucleus and cytomembrane. Knockout of CaSLP gene significantly decreased the pepper drought tolerance, while transient expression of CaSLP leads to drought tolerance in pepper, and overexpression of the CaSLP dramatically increased the drought stress tolerance in Arabidopsis. Furthermore, exogenous spring salicylic acid enhanced drought tolerance. The characterization of resistance molecular mechanisms in the Pseudomonas syringae pv. Tomato DC3000 (Pst.DC3000) is of great significance for the pepper yield and quality, we found that CaSLP-knockdown pepper plants demonstrated decreased Pst.DC3000 tolerance, whereas ectopic expression of the CaSLP increased the Pst.DC3000 stress tolerance in Arabidopsis. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) results showed that CaNAC035 physically interacts with CaSLP in the cell nucleus, and the CaNAC035 was identified as an upstream partner of the CaPR1 promoter and activated the transcription. Taken together, our data demonstrated that CaSLP plays an essential role in the regulation of drought stress. Our study elucidates the roles of CaSLP response to drought stress tolerance. Furthermore, a possible regulatory model and molecular mechanisms under drought stress is proposed.

This study provides a thorough exploration of the mechanisms regulating the onset of flowering in peach trees, a process principally governed by bud-dormancy. We applied untargeted metabolomics combined with a comprehensive series of molecular and biochemical experiments to scrutinize the variations in bloom times among different peach cultivars. The impact of exogenous chemical stimuli, specifically ethephon (ET) and abscisic acid (ABA), on bloom times was also evaluated. Our study revealed that the ET-induced delay in bloom time was associated with higher levels of proanthocyanidin (PA) compared to anthocyanins (ACNs) during endodormancy. Furthermore, fluctuations in the PA/ACNs ratio during dormancy demonstrated a strong correlation with the chill requirements and bloom dates of 12 distinct peach genotypes. The research further uncovers the crucial role of ABA in regulating the biosynthesis of PAs and ACNs during peach tree dormancy. Intriguingly, the exogenous application of ABA during endodormancy resulted in a reduction of PA content, leading to an earlier bloom time. We also observed variations in DAM gene expression between early- and late-blooming cultivars. The late-blooming cultivars exhibited higher transcript levels of DAM genes, elevated PA levels, and lower ABA levels compared to their early-blooming counterparts. Importantly, our study proposes PAs and ACNs as quantitative marker metabolites for endo- and ecodormancy phases. This innovative finding paves the way for developing more accurate chill and heat requirement models, thereby enabling a more precise understanding and projection of the impacts of global climate change on the phenology of tree fruit species.

Leaf senescence is a programmed plant developmental process that can also be regulated by environmental factors, like nutrient availability. Although phosphorus is an essential element determining plants growth and productivity, mechanisms underlying adaptation to phosphorus availability in plants are not well understood. In this study, we combined physiological, biochemical and molecular approaches to investigate the effect of phosphate supply on leaf senescence in rice. We show that short-term treatment of rice seedlings with low phosphate increases photosynthetic pigments content, confers tolerance to methyl viologen-induced oxidative stress in chloroplasts, and increases antioxidant enzyme activities. Leaves from low-Pi-treated plants also showed a reduction in membrane lipid peroxidation and electrolyte leakage. Opposite trends were observed in seedlings under high Pi supply, in which accelerated leaf senescence occurs. Further analyses indicated that CRISPR/Cas9-mediated editing of MIR827, and subsequent reduction in Pi content, promotes delayed leaf senescence, while Pi accumulation in MIR827 or MIR399 overexpressing plants accelerates senescence. These findings strongly support that short treatment with low phosphate delays rice leaf senescence. Transcriptomic analysis demonstrated multiple biological processes underlying adaptation of rice plants to low phosphate, including senescence-associated and metabolic processes. These findings provide novel insights into leaf senescence potentially contributing to sustainable rice production.

The HD-ZIP transcription factor family plays crucial roles in plant growth and abiotic stress responses. While its diverse functions and regulatory mechanisms are well-documented, its role in conferring abiotic stress tolerance in peaches remains largely unexplored. Here, we report the bioinformatics profile of PpGL2, a member of the HD-ZIP transcription factor family, and its integration into the soybean genome to assess its potential impact on drought tolerance. Localization studies in onion cells revealed nuclear localization of PpGL2-GFP fusion protein, while yeast hybridization experiments demonstrated its transactivation and DNA binding abilities. PpGL2 overexpression under drought conditions led to reduced accumulation of reactive oxygen species and malondialdehyde compared to wild-type, decreased water loss rate, and increased chlorophyll content and relative water content. Additionally, PpGL2 overexpression promoted plant height and root length under drought stress, accompanied by altered transcription levels of stress-related genes across different plant genotypes. Furthermore, PpGL2 overexpression enhanced oxidative tolerance. Therefore, our findings suggest that PpGL2 overexpression holds promise for enhancing soybean drought resistance, offering a novel approach to improving soybean drought resistance.

The plant hormone auxin plays a crucial role in regulating important functions in strawberry fruit development. Although a few studies have described the complex auxin biosynthetic and signaling pathway in wild diploid strawberry (Fragaria vesca), the molecular mechanisms underlying auxin biosynthesis and crosstalk in octoploid strawberry fruit development are not fully characterized. To address this knowledge gap, comprehensive transcriptomic analyses were conducted at different stages of fruit development and compared between the achene and receptacle to identify developmentally regulated auxin biosynthetic genes and transcription factors during the fruit ripening process. Similar to wild diploid strawberry, octoploid strawberry accumulates high levels of auxin in achene compared to receptacle. Consistently, genes functionating in auxin biosynthesis and conjugation, such as TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAAs), YUCCA (YUCs), and GRETCHEN HAGEN 3 (GH3s) were found to be primarily expressed in the achene, with low expression in the receptacle. Interestingly, several genes involved in auxin transport and signaling like PIN-FORMED (PINs), AUXIN/INDOLE-3-ACETIC ACID proteins (Aux/IAAs), TRANSPORT INHIBITOR RESPONSE 1 / AUXIN-SIGNALING F-BOX (TIR/AFBs) and AUXIN RESPONSE FACTOR (ARFs) were more abundantly expressed in the receptacle. Moreover, by examining DEGs and their transcriptional profiles across all six developmental stages, we identified key auxin-related genes co-clustered with transcription factors from the NAM-ATAF1,2-CUC2/ WRKYGQK motif (NAC/WYKY), BASIC REGION/ LEUCINE ZIPPER motif (bZIP), and APETALA2/Ethylene Responsive Factor (AP2/ERF) groups. These results elucidate the complex regulatory network of auxin biosynthesis and its intricate crosstalk within the achene and receptacle, enriching our understanding of fruit development in octoploid strawberries.

Restoration factors (Rfs) belonging to the pentatricopeptide repeat proteins (PPRs) family play an essential role in plant growth and development including their binding to CMS-associated mitochondrial RNAs leading to fertility restoration. The present study identified 22 mitochondrial-specific PPRs in pigeonpea and explored the underlying mechanisms of restoration of fertility in the A4 CMS system through yeast-three hybrid studies. The identified gene was functionally validated through transgenic expression in Arabidopsis model system and obtained conclusive evidence that the identified Rf-PPR was responsible for fertility restoration. The sub-cellular localization studies implied that the identified Rf-PPR is mitochondrial targeting. The study demonstrated that due to the interaction between mitochondrial CMS mRNA and nuclear Rf-PPR protein, post-transcriptional modification occurred, leading to the inability to translate and accumulate cytotoxic CMS protein resulting in fertility restoration. The study specifically looks into the RNA-protein interaction occurring at the nucleo-cytoplasmic level in the A4 cytoplasm of Cajanus cajanifolius. HighlightsThe study identifies the restoration of fertility genes corresponding to the CMS-causing orf147 gene.

AO_SCPLOWBSTRACTC_SCPLOWThis study investigates the resilience of two genotypes of Oryza sativa (rice) with varying levels of tolerance to drought stress, focusing on their production of reactive oxygen species (ROS) and chlorophyll retention when exposed to Xanthomonas oryzae infection. A total of 36 high ATT (AC 39000) and low ATT (BPT5204) plants were subjected to three drought treatments: 100% field capacity (control), gradual drought (reduction to 50% field capacity over 10 days), and rapid drought (immediate reduction to 50%). ROS production was quantified using Evans Blue staining and thiobarbituric acid reactive substances (TBARS) assays, while chlorophyll content was measured using the Arnon method. Membrane damage was higher in the control and rapid stress groups (971 and 1053 ng respectively) compared to gradual drought stress (848.5 ng) on day 12. High-tolerance genotypes demonstrated superior ROS regulation under gradual drought conditions, with the Evans Blue content exceeding that of low-tolerance genotypes by 13 ng. Similarly, chlorophyll retention was significantly higher (p = 0.0005) in high tolerance genotypes (1.166 mg {middle dot} g-1 FW) compared to low tolerance genotypes (0.966 mg {middle dot} g-1 FW). The results indicate that gradual drought stress increases resilience to bacterial infection through enhanced ROS-scavenging mechanisms, which is accentuated in the High ATT genotype, allowing for the development of dual resistant rice varieties capable of withstanding both abiotic and biotic stresses.