The Plant Journal最新文献

Global warming is harmful to plants and threatens crop yields in the world. In contrast to other abiotic stresses, the molecular mechanisms for plant high temperature perception and signaling are still not fully understood. Here, we report that transcription factor DREB AND EAR MOTIF PROTEIN 4 (DEAR4) positively regulates heat tolerance in Arabidopsis thaliana. We further reveal that DEAR4 proteins undergo liquid–liquid phase separation (LLPS) and high temperature could induce DEAR4 condensate formation in the nucleus. Moreover, DEAR4 recruits the transcriptional co-repressor TOPLESS (TPL) into the nuclear speckles under high temperature. The high temperature triggered DEAR4-TPL co-condensates enhance their transcriptional repression activity through modulating histone deacetylation levels of GASA5, which is a reported negative regulator of HEAT SHOCK PROTEINs (HSPs). A genome-wide transcriptional landscape study confirms that DEAR4 induces the expression of multiple HSPs. Taken together, we illustrate a transcriptional repression mechanism mediated by DEAR4 through LLPS to confer plants thermotolerance and open a new avenue for translating this knowledge into crops for improving their heat resistance.

Character displacement refers to the process by which species diverge more in sympatry due to competition for resources. This competition-driven speciation can also occur within populations, known as intraspecific character displacement (ICD). ICD can promote divergence within species by influencing intraspecific competition or encouraging the evolution of alternative phenotypes. Despite its significance, ICD remains understudied and requires further exploration. In this study, we investigate how competition influences genetic and morphological differentiation within species in sympatric and allopatric populations. We focused on Quercus serrata (in China and Japan) and Q. serrata var. brevipetiolata (found only in China), which belong to a small monophyletic group of oak species nested within Section Quercus (white oaks). Using genetic markers, we detected divergence between Chinese and Japanese populations and further diversification within China, with asymmetric historical gene flow primarily from Q. serrata (the earlier diverged species) to Q. serrata var. brevipetiolata (the later variety). Although genetic differentiation did not differ between sympatric and allopatric populations, leaf morphological variation, analyzed through the geometric morphometric method (GMM) and traditional morphological method, revealed greater trait variation in sympatry. In addition, we found an allometric growth relationship between leaf size and leaf mass of Q. serrata and Q. serrata var. brevipetiolata, with the leaf area of Q. serrata var. brevipetiolata decreasing more disproportionately to leaf mass. This suggests a resource trade-off, where Q. serrata var. brevipetiolata, the later diverged variety, adopts more resource-conservative traits in sympatry. Further analysis of trait variation with environmental factors supports these findings, while genetic variation along climate gradients showed significant responses primarily in Q. serrata, regardless of sympatric or allopatric conditions. Although neutral genetic markers are insufficient to capture selection-driven adaptive differentiation, we inferred that Q. serrata var. brevipetiolata is progressing towards ecological divergence from Q. serrata. Overall, our results highlight the role of ICD in driving morphological diversification and resource-use strategies within species in response to competitive pressures.

The complex and mutual interactions between plants and their associated microbiota are key for plant survival and fitness. From the myriad of microbes that exist in the soil, plants dynamically engineer their surrounding microbiome in response to varying environmental and nutrient conditions. The notion that the rhizosphere bacterial and fungal community acts in harmony with plants is widely acknowledged, yet little is known about how these microorganisms interact with each other and their host plants. Here, we explored the interaction of two well-studied plant beneficial endophytes, Enterobacter sp. SA187 and the fungus Serendipita indica. We show that these microbes show inhibitory growth in vitro but act in a mutually positive manner in the presence of Arabidopsis as a plant host. Although both microbes can promote plant salinity tolerance, plant resilience is enhanced in the ternary interaction, revealing that the host plant has the ability to positively orchestrate the interactions between microbes to everyone's benefit. In conclusion, this study advances our understanding of plant–microbiome interaction beyond individual plant–microbe relationships, unveiling a new layer of complexity in how plants manage microbial communities for optimal growth and stress resistance.

In plants, dehydroascorbate reductase (DHAR) is one of the key enzymes in AsA generation during the AsA-GSH cycle, which helps maintain the normal metabolic level of AsA. However, the molecular mechanism of DHAR's response to salt stress is still unknown. Our experiments show a ping-pong mechanism, in which DHA is combined with free reductase DHAR, and free reductase DHAR is combined with GSH in the form of sulfenylation to promote AsA generation in response to salt stress. This mechanism is inhibited by H₂O₂-mediated sulfenylation modification. The overexpression of PbDHAR3 in pear callus and Arabidopsis plants alleviated salt-induced damage, while its silencing decreased salt tolerance in Pyrus betulaefolia. PbNAC3 can activate the expression of PbDHAR3 by directly binding to the promoter. The overexpression of PbNAC3 in pear callus improved salt tolerance, while silencing it reduced tolerance in P. betulaefolia. Overexpression of PbNAC3 in Arabidopsis plants is able to adjust the trade-off between plant growth and salt stress. Higher expression levels of NCEDs or PYLs, and higher ABA content were observed under salt treatment. Further experiments demonstrate that PbNAC3 activates PbNCED5 through interaction with cis-regulatory elements. Overall, our results show that PbNAC3 plays a critical role in salt stress response by targeting the promoters of PbDHAR3 and PbNCED5, promoting AsA generation and ABA biosynthesis. This study will deepen our understanding of the mechanisms underlying the trade-offs between plant growth and stress tolerance and assist the development of stress-resistant, high-yield crops.

Cell division and differentiation within the shoot apical meristem (SAM) are essential for the morphogenesis of aboveground plant organs. This study reveals that the boundary genes OsNAM and OsCUC3 collaboratively maintain SAM activity. Loss of function in both OsNAM and OsCUC3 during the fourth leaf stage reduced SAM size, with the osnam oscuc3 mutant exhibiting abnormal leaf number and morphology. Furthermore, OsNAM and OsCUC3 inhibited the growth of axillary shoots. In the osnam oscuc3 mutant, the number of new leaves decreased, while buds in the coleoptile and the axil of the first leaf developed into tillers. Since OsNAM and OsCUC3 are involved in regulating both SAM activity and the growth of lateral shoots, we examined their expression patterns at the base of the main shoot. β-Glucuronidase (GUS) reporter activity and GFP reporter lines demonstrated that OsNAM and OsCUC3 have distinct expression patterns. Specifically, OsNAM was expressed throughout the SAM, whereas OsCUC3 was expressed only at the base of the SAM, with its expression gradually decreasing as seedlings develop. RNA sequencing analysis showed that the expression of genes related to leaf epidermal cell development, cell wall components, and hormonal signal transduction was altered in response to the loss of function of OsNAM and OsCUC3. Therefore, the boundary genes OsNAM and OsCUC3 not only inhibit the growth of axillary shoots but also regulate the development of aboveground organs, including leaf morphology and number, by maintaining the SAM activity in the main shoot.

The sugar content serves as the fundamental metabolic component that determines both the flavor quality and the nutritional value of fruits. Nevertheless, the regulatory mechanism underlying the rapid accumulation of sugars during citrus fruit maturation remains elusive. In this study, we demonstrated that the expression level of sucrose transporter CsSUT2 is increased during citrus fruit ripening and sugar accumulation. Functional assays confirmed that CsSUT2 is localized in the plasma membrane and exhibits sucrose transporter activity. Homologous and heterologous overexpression of CsSUT2 in citrus juice sacs, calli, and tomato resulted in an increase in sugar content. Conversely, virus-induced gene silencing and RNAi-mediated silencing of CsSUT2 led to a decrease in sugar levels in transgenic citrus tissues. We further identified CsMYBS3 as an upstream transcription factor that positively regulates the expression of CsSUT2. Transgenic evidence supported that the induction of sugar accumulation by CsMYBS3 depends on the transcript level of CsSUT2. Additionally, we found that CsbHLH122 physically interacts with CsMYBS3 to form a transcription factor complex, enhancing promoter transcriptional activity of CsSUT2. This study expands our understanding of the function and regulatory mechanism of sugar transporter in citrus, providing valuable insights for regulating sugar accumulation and quality control in citrus fruit.

Bamboo is known for its fast growth, and non-structural carbohydrates (NSCs) play a pivotal role in bamboo's fast growth. Despite extensive research on bamboo's growth, the role of NSCs, especially the underlying molecular regulatory mechanisms, in bamboo's fast growth remains largely unexplored. By studying growth patterns in various bamboo species, it was found that NSCs are transferred from mature bamboo to young shoots, facilitating their fast growth. This review explores NSCs in bamboo, covering their content, distribution, storage, and enzyme activities. It examines NSCs' physiological roles, including mobilization, transport, and growth facilitation, and discusses potential molecular regulatory mechanisms. It also summarizes the gene expression patterns involved in NSC synthesis and metabolism during bamboo's fast growth. NSCs regulate genes related to sugar transport, cell division, energy metabolism, and cell wall synthesis, thereby regulating bamboo's fast growth. NSCs interact with hormone signaling networks. Lastly, winter drought and cold stress stimulate NSC storage and transport. These stressors potentially serve as signals or prerequisites for NSC transport and accumulation. In general, this review summarizes the research progress on NSC transport from bamboo and its impact on bamboo's fast growth, providing a foundation for enhancing understanding and investigation of bamboo's fast growth mechanisms.