Aug 2026· New Phytologist· Vol 252, pp. 222-240· 0 citations· 70 references
Medicine
TL;DR
This study reveals how lipid metabolism, auxin homeostasis, and membrane dynamics intersect to shape hypocotyl adaptive responses, thereby optimizing growth under high‐temperature conditions.
Abstract
Cell elongation is a fundamental process in plant growth and development, and it is significantly affected by temperature changes. While the signaling mechanisms driving high‐temperature‐induced cell elongation have been extensively studied, the strategies plants employ to counteract excessive temperature‐induced elongation remain poorly understood. Using Arabidopsis thaliana hypocotyls as a model, we show that high temperature induces the triacylglycerol biosynthetic enzyme DGAT2, which acts as a growth‐restraining regulator that counterbalances auxin‐driven elongation. Auxin, in turn, downregulates DGAT2 expression, establishing a feedback loop that limits excessive hypocotyl elongation under high temperature. Thermo‐ and auxin‐responsive regulation of DGAT2, and its role in modulating membrane lipid order, are conserved between Arabidopsis and Camelina, indicating a shared DGAT2–auxin regulatory module. Our study reveals how lipid metabolism, auxin homeostasis, and membrane dynamics intersect to shape hypocotyl adaptive responses, thereby optimizing growth under high‐temperature conditions.
Triacylglycerol (TAG) accumulation and abiotic stress tolerance are critical for woody oil crop productivity, yet their coordination remains poorly understood. Here, we characterized CcDGAT1, a diacylglycerol acyltransferase 1 gene from hickory (Carya cathayensis) that links oil accumulation with aluminum (Al) tolerance. CcDGAT1 was highly expressed in developing kernels and vegetative tissues and was strongly induced by Al stress. CcDGAT1 overexpression increased total oil content and unsaturated fatty acid levels and enhanced Al tolerance, as shown by improved membrane integrity, root growth, and biomass. Under Al stress, CcDGAT1 overexpression promoted the accumulation of 18:2/18:3‐containing TAGs while reducing 18:2/18:3‐enriched membrane lipid pools. Consistent with this protective role, transient silencing of CcDGAT1 in hickory roots aggravated Al‐induced lipid peroxidation and electrolyte leakage. Dual‐luciferase, yeast one‐hybrid, and electrophoretic mobility shift assays demonstrated that CcATML1 and CcWRKY11a directly activate CcDGAT1 transcription. Overexpression of these transcription factors increased CcDGAT1 expression, fatty acid content, membrane integrity, and Al tolerance. Together, these findings establish CcDGAT1 as a functional oil‐promoting DGAT1 in hickory and support a model in which CcDGAT1‐associated lipid remodeling contributes to Al‐stress protection. The CcATML1/CcWRKY11a‐CcDGAT1 module further provides a transcriptional framework for linking lipid metabolism with stress resilience in woody oil crops.
Shan Zheng, Wenchao Chen, Jiaqi Zhang et al.· New Phytologist· 0 citations
Plants must balance growth with stress adaptation, yet the transcriptional mechanisms governing this trade-off remain incompletely defined. Here, we identify the MADS-box transcription factor (TF) AGL103 as a promoter of growth but a negative regulator of drought and salt tolerance in Arabidopsis thaliana. agl103 mutants exhibit enhanced germination, root elongation, and survival under mannitol-induced osmotic stress and salt stress, whereas AGL103-overexpressing plants are hypersensitive. Transcriptomic and molecular analyses show that AGL103 directly represses MYB15 and MYB102 by binding CArG motifs in their promoters. Notably, AGL103 also physically interacts with Teosinte branched 1/Cycloidea/ Proliferating cell factor (TCP) proteins TCP14 and TCP15, forming a repressor complex that reinforces MYB15/MYB102 suppression and antagonizes TCP14-mediated transcriptional activation. Furthermore, TCP14, but not TCP15, feeds back to repress AGL103 transcription, establishing a regulatory loop that fine-tunes plant growth and stress responses. This AGL103-TCPs module integrates developmental and stress signaling, offering mechanistic insight into how plants balance growth and resilience and highlighting potential targets for engineering stress-tolerant crops.
Lan Yang, Die Liu, Jing Zhang et al.· Plant Communications· 0 citations
SUMMARY Shade avoidance is a key adaptive growth response that enables plants to compete for light under dense vegetation. In Arabidopsis thaliana, the transcription factor PHYTOCHROME‐INTERACTING FACTOR 7 (PIF7) is dephosphorylated under shade and accumulates into the nucleus to promote shade‐induced elongation growth through activation of auxin biosynthesis/signaling genes, yet the molecular mechanism underlying PIF7 dephosphorylation under shade conditions has remained unclear. Using yeast two‐hybrid screening and extensive biochemical, genetic, and photobiological analyses, we identified protein phosphatase 2A (PP2A) as a direct regulator of PIF7 activity. We show that four PP2A regulatory subunits, B′α, B′β, B″α, and B″β, associate with PIF7 both in vitro and in vivo. Genetic analyses demonstrate that loss of PP2A B′α, B′β, B″α, and B″β function reduces hypocotyl elongation under shade, whereas overexpression of these subunits enhances shade‐induced growth. Epistasis analyses further reveal that PP2A acts in the same genetic pathway as PIF7 to regulate hypocotyl elongation during shade avoidance. Consistently, expression of PIF7 target genes is attenuated in pp2a mutants under shade conditions, and immunopurified PP2A complexes efficiently dephosphorylate PIF7 in vitro. Together, our findings establish a direct biochemical role for PP2A in PIF7 activation and reveal a new role for PP2A in regulating shade responses in plants.
Xingbo Cai, Oihik Mitra, Amariah Gustamante et al.· The Plant Journal· 0 citations
Temperature shapes plant biology, affecting everything from molecular biophysics to whole‐organism development. Because plant cellular temperature typically matches ambient conditions, cellular processes are inherently affected by temperature. Plants continuously integrate thermal cues in growth and development decisions. Auxin signaling is central to this integration, coordinating transcriptional, physiological, and morphological responses during thermomorphogenesis. Here, we synthesize how temperature modulates auxin signaling across scales. At the biophysical level, temperature alters protein conformation, interaction kinetics, and phase behavior, influencing key interactions such as TIR1/AFB–Aux/IAA binding and ARF oligomerization. Many of the temperature‐sensing pathways affect auxin biosynthesis, transport, partitioning, and signal transduction, ultimately shaping thermomorphogenic growth. In this review, we explore these findings that position auxin signaling as a direct and key integrator of temperature information.
K. Sageman-Furnas, Lucia C. Strader· New Phytologist· 0 citations
A positive feedback loop between CLV3 and WUS that is mediated by multiple hormone interactions, which is critical for plants to adapt to harsh environments is revealed.
Mengchu Xu, Haijun Wu, Chengwu Liu et al.· Molecular Plant· 0 citations
The m⁶A demethylase ALKBH10B emerges as a crucial post-transcriptional regulator of hormonal crosstalk, photosynthetic maintenance, and mitochondrial energy metabolism to fine-tune plant stress adaptation to drought. Epitranscriptomic N⁶-methyladenosine (m⁶A) mRNA modification has emerged as an important regulatory layer of gene expression and protein synthesis in plant stress adaptation. In this study, expression profiling revealed that drought stress induces a global reprogramming of the m6A machinery in Arabidopsis thaliana, with the m6A demethylase ALKBH10B exhibiting a more pronounced time-dependent response. ALKBH10B transcription is induced by ABA, most likely via ABRE and MYB cis-elements, whereas jasmonate alleviates this activation. Moreover, ALKBH10B overexpressing plants (OX-1) accumulated wild type (WT) levels of ABA under drought stress but displayed a markedly reduced content in jasmonic acid (JA) and jasmonoyl-isoleucine (JA-Ile). They furthermore exhibit enhanced stomatal closure, improved water-use efficiency, and thus an enhanced drought tolerance. Transcriptome analysis revealed that drought stress induces fewer transcriptional changes in OX-1 plants compared to WT and the drought-sensitive alkbh10b-1 mutant. Differential expression and GO enrichment analyses highlight that photosynthesis-related processes were most affected by ALKBH10B activity, correlating with a preserved chlorophyll content and PSII efficiency in OX-1. Analysis by m⁶A-IP-qPCR showed that ALKBH10B directly demethylates specific photosynthesis-related and drought-responsive genes, while other transcripts are indirectly regulated by ALKBH10B-dependent processes. Moreover, transcripts associated with respiration were enriched in OX-1, indicating that ALKBH10B also supports mitochondrial energy metabolism during drought. Together, our results suggest that ALKBH10B enhances drought tolerance by coordinating m⁶A-dependent transcriptional and post-transcriptional regulation to maintain photosynthetic capacity and mitochondrial energy metabolism, as well as fine-tuning ABA-jasmonate crosstalk.