College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi Province, 710119, PR China.
Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, Shaanxi Province, 716000, PR China.
BMC Plant Biol. 2024 Jun 1;24(1):485. doi: 10.1186/s12870-024-05174-6.
Brassinosteroids (BRs) are a class of phytohormones that regulate a wide range of developmental processes in plants. BR-associated mutants display impaired growth and response to developmental and environmental stimuli.
Here, we found that a BR-deficient mutant det2-1 displayed abnormal root gravitropic growth in Arabidopsis, which was not present in other BR mutants. To further elucidate the role of DET2 in gravity, we performed transcriptome sequencing and analysis of det2-1 and bri1-116, bri1 null mutant allele. Expression levels of auxin, gibberellin, cytokinin, and other related genes in the two mutants of det2-1 and bri1-116 were basically the same. However, we only found that a large number of JAZ (JASMONATE ZIM-domain) genes and jasmonate synthesis-related genes were upregulated in det2-1 mutant, suggesting increased levels of endogenous JA.
Our results also suggested that DET2 not only plays a role in BR synthesis but may also be involved in JA regulation. Our study provides a new insight into the molecular mechanism of BRs on the root gravitropism.
油菜素内酯（BRs）是一类植物激素，调节植物发育过程中的广泛范围。BR 相关突变体表现出生长受损和对发育及环境刺激的响应受损。
在这里，我们发现 BR 缺陷突变体 det2-1 在拟南芥中表现出异常的根向重力性生长，而其他 BR 突变体则没有。为了进一步阐明 DET2 在重力中的作用，我们对 det2-1 和 bri1-116、bri1 缺失突变等位基因进行了转录组测序和分析。det2-1 和 bri1-116 两种突变体中生长素、赤霉素、细胞分裂素和其他相关基因的表达水平基本相同。然而，我们只发现 det2-1 突变体中大量 JAZ（茉莉酸 ZIM 结构域）基因和茉莉酸合成相关基因上调，表明内源 JA 水平升高。
我们的结果还表明，DET2 不仅在 BR 合成中起作用，而且可能参与 JA 调节。我们的研究为 BRs 对根向重力性的分子机制提供了新的见解。
