Salt stress is a major constraint on peanut ( Arachis hypogaea L.) productivity worldwide, yet the transcriptional regulatory networks coordinating root adaptation to salinity remain undefined in this allotetraploid crop. Here, we profiled the transcriptomes of seedling roots from a space-induced peanut mutant (ZHM6) under 0.5% NaCl treatment to systematically dissect salt-responsive transcriptional programs at network resolution. We identified 54,430 expressed genes and 3817 novel transcripts, substantially expanding the annotated peanut root transcriptome. A total of 4985 differentially expressed genes (DEGs) were identified, including 369 novel transcripts. These DEGs were enriched in secondary metabolite biosynthesis, including phenylpropanoid and diterpenoid pathways, and metabolic pathways. Protein-protein interaction (PPI) analysis of 209 salt-responsive transcription factors (TFs) revealed a core regulatory network of 167 interconnected TFs. The auxin-associated AT-hook TF AhAHL15 was prioritized for functional characterization. Heterologous overexpression in Arabidopsis thaliana enhanced salt tolerance through activation of auxin signaling. These findings establish a transcriptional regulatory framework for salt adaptation in peanut roots and inform molecular breeding of salt-tolerant varieties.
Neopestalotiopsis spp. has emerged as aggressive causal agents of strawberry crown rot, causing rapid plant decline and significant yield losses worldwide. Although disease symptoms are well documented, their impact on host photosynthetic performance remains unclear. The primary objective of this study was to characterize the temporal dynamics of leaf gas exchange following crown infection, while a secondary objective was to evaluate whether weekly applications of native Trichoderma strains modified this physiological trajectory under pathogen pressure. Strawberry plants were crown-inoculated with Neopestalotiopsis sp. and monitored for 21 days using repeated measurements of net photosynthesis ( A ), stomatal conductance ( g s ), transpiration ( E ), and intercellular CO₂ concentration ( C i ). Significant reductions in net photosynthesis (A) were detected by 3 days post-inoculation (dpi), preceding the first visible foliar symptoms observed at 7 dpi. Early reductions in stomatal conductance (gs) and transpiration (E) were also observed, consistent with stomatal involvement in the initial physiological response. At 21 dpi, net photosynthesis declined by approximately 75%, together with reductions in g ₛ (~63%) and E (~64%), while C ᵢ increased sharply (~36% relative to 14 dpi) and stomatal limitation index declined (~69%). This late-stage pattern suggests that stomatal restriction alone could not account for the photosynthetic decline. Trichoderma treatments did not consistently maintain gas exchange performance or prevent late-stage canopy decline during infection. Overall, Neopestalotiopsis crown infection induced temporally distinct physiological responses, progressing from early signs of stomatal restriction to severe late-stage photosynthetic decline accompanied by changes in internal CO₂ dynamics. This study provides a temporal characterization of leaf gas-exchange responses to Neopestalotiopsis crown infection in strawberry, highlighting changes in carbon assimilation before the first recorded visible foliar symptoms and evolving relationships among gas-exchange parameters during disease progression.
Leaf color mutations are rare in jujube trees, yet they serve as ideal materials for investigating the biosynthetic pathways of chlorophylls and carotenoids. To elucidate the molecular mechanism underlying leaf color mutation in jujube, this study compared the differences in pigment contents, genome-wide DNA methylation patterns and transcriptomic expression profiles among three distinct leaf phenotypes (green leaves, GL; spotted leaves, SL; albino leaves, WL) of the new jujube cultivar ‘Ruiyun’ at the seedling stage. The results revealed that WL exhibited the lowest contents of chlorophylls and carotenoids alongside severe degradation of chloroplast ultrastructure relative to GL. Among the three leaf types, the CG context displayed the highest methylation level. Combined methylome and transcriptome analyses revealed a significant correlation between DNA methylation modifications and the expression levels of key genes involved in chlorophyll and carotenoid biosynthesis pathways. These findings suggest that DNA methylation may play a candidate regulatory role in the variation of leaf color intensity in jujube, potentially by modulating the biosynthesis and degradation of photosynthetic pigments. This study provides novel insights into the mechanism underlying leaf color variation in jujube from epigenetic and transcriptional perspectives.
Neopestalotiopsis spp. has emerged as aggressive causal agents of strawberry crown rot, causing rapid plant decline and significant yield losses worldwide. Although disease symptoms are well documented, their impact on host photosynthetic performance remains unclear. The primary objective of this study was to characterize the temporal dynamics of leaf gas exchange following crown infection, while a secondary objective was to evaluate whether weekly applications of native Trichoderma strains modified this physiological trajectory under pathogen pressure. Strawberry plants were crown-inoculated with Neopestalotiopsis sp. and monitored for 21 days using repeated measurements of net photosynthesis (A), stomatal conductance (gs), transpiration (E), and intercellular CO₂ concentration (Ci). Significant reductions in net photosynthesis (A) were detected by 3 days post-inoculation (dpi), preceding the first visible foliar symptoms observed at 7 dpi. Early reductions in stomatal conductance (gs) and transpiration (E) were also observed, consistent with stomatal involvement in the initial physiological response. At 21 dpi, net photosynthesis declined by approximately 75%, together with reductions in gₛ (~63%) and E (~64%), while Cᵢ increased sharply (~36% relative to 14 dpi) and stomatal limitation index declined (~69%). This late-stage pattern suggests that stomatal restriction alone could not account for the photosynthetic decline. Trichoderma treatments did not consistently maintain gas exchange performance or prevent late-stage canopy decline during infection. Overall, Neopestalotiopsis crown infection induced temporally distinct physiological responses, progressing from early signs of stomatal restriction to severe late-stage photosynthetic decline accompanied by changes in internal CO₂ dynamics. This study provides a temporal characterization of leaf gas-exchange responses to Neopestalotiopsis crown infection in strawberry, highlighting changes in carbon assimilation before the first recorded visible foliar symptoms and evolving relationships among gas-exchange parameters during disease progression.
