Journal of Integrative Plant Biology最新文献

Leaf morphology varies substantially across plant species. In soybeans, the regulation of compound leaf development remains poorly characterized, despite its critical role in plant architecture. Some soybean cultivars have compound leaves with up to five leaflets, while most are trifoliolate. Using genetic mapping, we identified a gene behind the leaflet number variation as LF1, an AP2/ERF transcription factor. High expression levels of LF1 were further observed in leaf primordium initiation sites, leaf primordia, and leaflet initiation domains. Transgenic overexpression of LF1 increased leaflet number. Further investigation revealed that LF1 regulates leaflet development through negative autoregulation via GCC-box cis-element binding. In addition to the role of LF1, the CRISPR-edited mutant of TEOSINTE-BRANCHED1/CYCLOIDEA/PCF3 (GmTCP3) displayed serrated blade margins in juvenile leaves and increased compound leaflet numbers. Protein interaction assays confirmed LF1 binding affinity for GmTCP3. Furthermore, we demonstrate that LF1 induces the expression of GmLFY, a key regulator of leaflet development. Altogether, our findings establish LF1 as a central regulator of soybean leaflet morphogenesis and reveal its mechanistic interactions with GmTCP3 and LEAFY (GmLFY), offering novel mechanistic insights into the genetic control of compound leaf development.

Rice is one of the most important food crops in the world and it is prone to attack by many diseases, such as the rice blast, sheath blight, bacterial leaf blight, and so on. These diseases represent the main constraints in rice production, threatening food security and safety. Here, new control strategies against these major rice diseases have been developed either by heterologous expression of a pathogen effector UvScd1 from false smut fungus Ustilaginoidea virens or by spraying the engineered biocontrol agent Bacillus subtilis secreting the effector UvScd1. Compared to the wild-type rice Zhonghua11 (ZH11), the rice line heterologously expressing UvScd1 showed lesion mimics and upregulated the expression of defense-related genes in leaves, including genes related to the JA and SA signaling pathways. As expected, the transgenic rice line showed broad-spectrum resistance to hemibiotrophic fungus Magnaporthe oryzae, necrotrophic fungus Rhizoctonia solani, and bacterium Xanthomonas oryzae pv. oryzae (Xoo), while there was no effect on yield-related agronomic traits compared with ZH11, suggesting that the effector UvScd1 confers both plant resistance via induction of ROS and defense-related genes, and maintains the balance between plant resistance and yield. In field experiments, comparable control efficiencies against these major rice diseases were achieved by spraying B. subtilis engineered to secrete UvScd1 and corresponding chemical pesticides, underscoring that use of biocontrol agents to secrete certain pathogen effector proteins is an effective strategy for the management of plant diseases. It is noteworthy that the application of B. subtilis engineered to secrete UvScd1 also achieved effective control for a variety of crop diseases, suggesting its excellent potential for use in practice.

Drought stress and abscisic acid (ABA) have been known to play a critical role in modulating sugar accumulation in fruit, and yet, the underlying molecular mechanisms remain elusive. In this study, we have demonstrated that drought-mimicking film mulching increased sucrose levels in Satsuma mandarin (Citrus unshiu) fruit, coinciding with upregulation of CuSPS4, which encodes the sucrose phosphate synthase (SPS), in the transcriptome profiling. CuSPS4 was further shown to be drought- and ABA-inducible and functionally essential for sucrose synthesis. Mechanistically, two transcription factors, CuWRKY41 and CuWRKY23, directly bound to and activated the CuSPS4 promoter via the W-box element, with CuWRKY41 additionally regulating CuWRKY23 expression. Consistently, both CuWRKY41 and CuWRKY23 positively regulated sucrose synthesis by upregulating CuSPS4. Meanwhile, the substrate-interacting subunit (CuSnRK1β1) and catalytic subunit (CuSnRK1α) of SUCROSE NON-FERMENTING RELATED KINASE 1 (SnRK1) interacted with CuWRKY41, triggering CuSnRK1α-mediated phosphorylation and subsequent degradation of CuWRKY41, thereby suppressing its activation. However, ABA promoted cytoplasmic translocation of CuSnRK1α and CuSnRK1β1 and reduced nuclear interaction with CuWRKY41, leading to its phosphorylation alleviation and protein stabilization, concurrent with enhanced transcription activation of CuWRKY23 and CuSPS4. Taken together, these findings reveal a sophisticated regulatory mechanism whereby drought promotes sucrose accumulation by suppressing CuSnRK1α-mediated phosphorylation and degradation of CuWRKY41, enabling its transcriptional activation of CuSPS4 directly or via CuWRKY23. Our study provides significant insights into the molecular basis of drought-induced sucrose accumulation and presents valuable regulatory components that could be targeted for fruit quality improvement.

Waterlogging stress is a major abiotic stress that severely limits plant growth and development. However, little is known about the effects of waterlogging stress on the growth and development of gymnosperms. In this study, we demonstrated that the TgRAV1–TgWRKY74–TgACS13 module regulates ethylene-enhanced root vitality during waterlogging stress in the gymnosperm Torreya grandis. Root vitality, the physiological status of root tissues, reflects their metabolic activity and cell viability of roots. Waterlogging stress induces ethylene accumulation in T. grandis roots, thereby enhancing root vitality. The ethylene biosynthesis gene TgACS13 positively regulates root vitality under waterlogging stress by increasing ethylene levels. The transcription factors TgWRKY74 and TgRAV1 directly regulate TgACS13 expression by binding to its promoter. Furthermore, waterlogging stress activates TgWRKY74 to promote TgACS13 transcription and alleviates the inhibitory effect of TgRAV1 on its expression, resulting in ethylene-enhanced root vitality during waterlogging stress. In addition, TgRAV1 interacts with TgWRKY74 both in vivo and in vitro, reducing the transcriptional activity of TgWRKY74 by inhibiting its DNA-binding ability without affecting the transcriptional activity of TgRAV1. Therefore, the TgRAV1–TgWRKY74 module finely tunes TgACS13 expression to regulate ethylene accumulation through multiple mechanisms, thereby maintaining the vitality of T. grandis roots exposed to waterlogging stress.

The conversion of starch into sugar during postharvest banana (Musa acuminata, AAA group) ripening significantly influences fruit quality. Ethylene response factors (ERFs) regulate fruit ripening through ethylene signaling, while redox modifications affect their activity by post-translational changes. This study identifies MaERF95L, an EDLL-domain ERF in banana, as a central regulator of starch-to-sugar metabolism during postharvest ripening. Using electrophoretic mobility shift and dual-luciferase reporter assays, we demonstrate that MaERF95L directly binds to and activates the expression of six genes related to starch degradation and sucrose synthesis (MaGWD1, MaAMY3, MaBAM1, MaHK5, MaPGI1, and MaUPG3). MaERF95L overexpression accelerates starch degradation and sugar accumulation in both banana and tomato fruits during ripening. Notably, methionine (Met, M)-based oxidation modifications (e.g., Met-16 and Met-77) suppress MaERF95L's transcriptional regulatory function. Simulating oxidation by Met→glutamine (Gln, Q) substitutions (MaERF95L^M16Q/M77Q) alters its subcellular localization and also impairs its DNA-binding and transcriptional activation capabilities. In contrast, blocking oxidation by Met→Valine (Val, V) substitutions (MaERF95L^M16V/M77V) maintains its transcriptional activation activity. Furthermore, transient overexpression of MaERF95L^M16Q/M77Q in bananas reduced MaERF95L's activation of genes related to starch degradation and sucrose synthesis, and starch-to-sugar conversion. However, the overexpression of MaERF95L^M16V/M77V showed no effect on MaERF95L's activation function. These findings reveal a Met oxidation-sensitive regulatory mechanism connecting reactive oxygen species signaling to carbohydrate metabolism, providing molecular insights into quality formation regulation during ripening and potential strategies for reducing postharvest losses in climacteric fruits.