ELONGATED HYPOCOTYL5 (HY5) and HY5 HOMOLOGUE (HYH) maintain shade avoidance suppression in UV-B.
ELONGATED HYPOCOTYL5 (HY5) and HY5 HOMOLOGUE (HYH) maintain shade avoidance suppression in UV-B.
复制标题
ELONGATED HYPOCOTYL5 (HY5) 和 HY5 同源物 (HYH) 在 UV-B 中保持避荫抑制。
DOI：
10.1111/tpj.16328
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Sharma A
中科院分区：
文献类型：
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作者：
Sharma A
红远红光比(R：FR)的降低为植物提供了一个明确的植物遮荫信号，并由光敏色素感光器进行监测。植物将这些信息与其他环境线索结合起来，以确定侵占植被的距离和密度。对遮荫敏感的物种通过启动一系列称为遮荫回避的发育适应来响应R：FR的减少。这些措施包括伸长茎，以便于轻型觅食。下胚轴伸长是由光敏色素相互作用因子(PIF)4、5和7促进的生长素生物合成促进的。UV-B被UV抗性基因8(UVR8)感光受体感知的UV-B迅速抑制遮荫回避，部分是通过抑制PIF4/5转录积累和破坏PIF4/5蛋白的稳定。在这里，我们表明，长期的遮荫抑制是由加长的下胚轴5(HY5)和HY5同源基因(HYH)维持的，它们调节与激素信号和细胞壁修饰有关的基因的转录重编程。HY5和HYH在UV-B中升高，并抑制参与细胞壁松动的XYLOGLUCAN EndoTRANSGLUCOSYLASE/HYH(Xth)基因的表达。它们还增加了GA2-OXIDASE 1(GA2ox1)和GA2ox2的表达，编码赤霉素分解代谢酶，这些酶冗余地作用于稳定PIF抑制的Della蛋白。因此，UVR8调节时间上不同的信号通路，首先快速抑制并随后维持对UV-B暴露后遮荫回避的抑制。
Reductions in red to far‐red ratio (R:FR) provide plants with an unambiguous signal of vegetational shade and are monitored by phytochrome photoreceptors. Plants integrate this information with other environmental cues to determine the proximity and density of encroaching vegetation. Shade‐sensitive species respond to reductions in R:FR by initiating a suite of developmental adaptations termed shade avoidance. These include the elongation of stems to facilitate light foraging. Hypocotyl elongation is driven by increased auxin biosynthesis promoted by PHYTOCHROME INTERACTING FACTORs (PIF) 4, 5 and 7. UV‐B perceived by the UV RESISTANCE LOCUS 8 (UVR8) photoreceptor rapidly inhibits shade avoidance, in part by suppressingPIF4/5transcript accumulation and destabilising PIF4/5 protein. Here, we show that longer‐term inhibition of shade avoidance is sustained by ELONGATED HYPOCOTYL 5 (HY5) and HY5 HOMOLOGUE (HYH), which regulate transcriptional reprogramming of genes involved in hormone signalling and cell wall modification. HY5 and HYH are elevated in UV‐B and suppress the expression ofXYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE(XTH) genes involved in cell wall loosening. They additionally increase expressionGA2‐OXIDASE1(GA2ox1) andGA2ox2, encoding gibberellin catabolism enzymes that act redundantly to stabilise the PIF‐inhibiting DELLA proteins. UVR8 therefore regulates temporally distinct signalling pathways to first rapidly inhibit and subsequently maintain suppression of shade avoidance following UV‐B exposure.