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Abscisic acid (ABA) is one of the most important phytohormones involved in stress responses in plants. However, knowledge of the effect on ABA distribution and transport of water stress at different sites on the plant is limited. In this study, water stress imposed on peanut leaves or roots by treatment with PEG 6000 is termed "leaf stress" or "root stress", respectively. Immunoenzyme localization technolony was first used to detect ABA distribution in peanut. Under root stress, ABA biosynthesis and distribution level were all more pronounced in root than in leaf. However, ABA transport and the ability to induce stomatal closure were still better in leaf than in root during root stress; However, ABA biosynthesis initially increased in leaf, then rapidly accumulated in the vascular cambium of leaves and induced stomatal closure under leaf stress; ABA produced in root tissues was also transported to leaf tissues to maintain stomatal closure. The vascular system was involved in the coordination and integration of this complex regulatory mechanism for ABA signal accumulation. Water stress subject to root or leaf results in different of ABA biosynthesis and transport ability that trigger stoma close in peanut.

Pre-harvest sprouting (PHS) is one of the most important factors having adverse effects on yield and grain quality all over the world, particularly in wet harvest conditions. PHS is controlled by both genetic and environmental factors and the interaction of these factors. Breeding varieties with high PHS resistance have important implications for reducing yield loss and improving grain quality. The rapid advancements in the wheat genomic database along with transcriptomic and proteomic technologies have broadened our knowledge for understanding the regulatory mechanism of PHS resistance at transcriptomic and post-transcriptomic levels. In this review, we have described in detail the recent advancements on factors influencing PHS resistance, including grain color, seed dormancy, α-amylase activity, plant hormones (especially abscisic acid and gibberellin), and QTL/genes, which are useful for mining new PHS-resistant genes and developing new molecular markers for multi-gene pyramiding breeding of wheat PHS resistance, and understanding the complicated regulatory mechanism of PHS resistance. [ABSTRACT FROM AUTHOR]

Heat shock transcription factors (Hsfs) play multifaceted roles in plant growth, development, and responses to environmental factors. However, their involvement in seed dormancy and germination processes has remained elusive. In this study, we identified a wheat class B Hsf gene, TaHsf-7A , with higher expression in strong-dormancy varieties compared to weak-dormancy varieties during seed imbibition. Specifically, TaHsf-7A expression increased during seed dormancy establishment and subsequently declined during dormancy release. Through the identification of a 1-bp insertion (ins)/deletion (del) variation in the coding region of TaHsf-7A among wheat varieties with different dormancy levels, we developed a CAPS marker, Hsf-7A-1319, resulting in two allelic variations: Hsf-7A-1319-ins and Hsf-7A-1319-del. Notably, the allele Hsf-7A-1319-ins correlated with a reduced seed germination rate and elevated dormancy levels, while Hsf-7A-1319-del exhibited the opposite trend across 175 wheat varieties. The association of TaHsf-7A allelic status with seed dormancy and germination levels was confirmed in various genetically modified species, including Arabidopsis, rice, and wheat. Results from the dual luciferase assay demonstrated notable variations in transcriptional activity among transformants harboring distinct TaHsf-7A alleles. Furthermore, the levels of abscisic acid (ABA) and gibberellin (GA), along with the expression levels of ABA and GA biosynthesis genes, showed significant differences between transgenic rice lines carrying different alleles of TaHsf-7A. These findings represent a significant step towards a comprehensive understanding of TaHsf-7A 's involvement in the dormancy and germination processes of wheat seeds. • The class B Hsf gene TaHsf-7A is highly expressed in wheat grains. • Transgenic experiments confirmed TaHsf-7A's crucial role in seed dormancy regulation. • AtHsfB2b and TaHsf-7A have functional similarity in regulating seed dormancy. • TaHsf-7A is involved in the ABA and GA signaling pathways to regulate seed dormancy. [ABSTRACT FROM AUTHOR]

Late embryogenesis abundant (LEA) proteins play important roles in plant development and responses to diverse stresses. However, their specific roles in seed dormancy and germination remain unclear. In this study, we identified TaLEA-1A , an LEA gene highly expressed in wheat seeds and differentially expressed in imbibed seeds of weak-dormancy variety Jing 411 (J411) and strong-dormancy variety Hongmangchun 21 (HMC21). Sequence analyses revealed 14 variations in the promoter and coding regions of TaLEA-1A between J411 and HMC21. Subsequent validation established associations of a single nucleotide polymorphism (SNP) in the promoter (-1366 bp, G/A) and an insertion/deletion (Indel) variation in the coding region (+345 bp, -/C) with seed dormancy and germination across 192 wheat varieties. Furthermore, the effects of the strong-dormancy allele TaLEA-1A-345-ins and weak-dormancy allele TaLEA-1A-345-del on seed dormancy and germination were confirmed using transgenic Arabidopsis and rice lines as well as J411 mutant induced with ethyl methane sulphonate. Analyses of endogenous hormone contents and expression patterns suggested that TaLEA-1A may regulate seed dormancy and germination by mediating gibberellic acid and abscisic acid balance. These findings not only contribute to unraveling the intricate regulatory network governing seed dormancy and germination in wheat and other plants but also provide a favorable gene and molecular marker for genetic improvement of wheat PHS resistance. • Role of wheat Late embryogenesis abundant gene TaLEA-1A in seed germination and dormancy. • Discovery of a superior haplotype of TaLEA-1A for PHS resistance in wheat. • We verified the role of TaLEA-1A in seed dormancy and germination using transgenic Arabidopsis and rice materials, along with a wheat EMS mutant. • TaLEA-1A may regulate seed dormancy and germination by affecting GA and ABA metabolism and signal transduction pathways. [ABSTRACT FROM AUTHOR]