SPL14/17 act downstream of strigolactone signalling to modulate rice root elongation in response to nitrate supply
SPL14/17 act downstream of strigolactone signalling to modulate rice root elongation in response to nitrate supply
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DOI：
10.1111/tpj.15188
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发表时间：
2021-03-17
期刊：
影响因子：
7.2
通讯作者：
Zhao, Quanzhi
中科院分区：
文献类型：
--
作者：
Sun, Huwei;Guo, Xiaoli;Zhao, Quanzhi
氮（N）是粮食作物必需的主要营养素。虽然铵态氮（NH 4+）是水稻的主要氮源，但硝酸盐（NO3-）也可以被吸收利用。水稻对NO3-的反应是通过改变其根系形态，如根伸长。独脚金内酯（SL）是根长的重要调节剂。然而，SL及其下游基因在NO3-诱导的根伸长中的作用尚不清楚。在这里，总N和SL（4-脱氧列当）和种子根（SR）长度的响应，以NH 4+和NO3-的水平在水稻植株进行了研究。NO3促进SR伸长，可能是由于短期信号感知和长期营养功能。与NH 4+条件相比，NO3-处理的水稻植株根中记录了更高的SL信号/水平和更少的D53蛋白。与野生型植物相比，SR长度的d突变体是响应NO3-条件，和应用程序的rac-GR 24（SL类似物）恢复SR长度在d10（SL生物合成突变体），但不是在d3，d14，和d53（SL响应突变体），这表明更高的SL信号/水平参与NO3-诱导的根伸长。D53与SPL 17相互作用并抑制SPL 17介导的来自PIN 1b启动子的反式激活。SPL 14/17和PIN 1b的突变导致根伸长对NO3-和rac-GR 24应用的不敏感性。因此，我们得出结论，SL的感知D14导致D53通过蛋白酶体系统降解，这释放了抑制SPL 14/17调节转录的PIN 1b，导致根伸长NO3-供应。
Nitrogen (N) is an essential major nutrient for food crops. Although ammonium (NH4+) is the primary N source of rice (Oryza sativa), nitrate (NO3-) can also be absorbed and utilized. Rice responds to NO3- application by altering its root morphology, such as root elongation. Strigolactones (SLs) are important modulators of root length. However, the roles of SLs and their downstream genes in NO3--induced root elongation remain unclear. Here, the levels of total N and SL (4-deoxyorobanchol) and the responses of seminal root (SR) lengths to NH4+ and NO3- were investigated in rice plants. NO3- promoted SR elongation, possibly due to short-term signal perception and long-term nutrient function. Compared with NH4+ conditions, higher SL signalling/levels and less D53 protein were recorded in roots of NO3--treated rice plants. In contrast to wild-type plants, SR lengths of d mutants were less responsive to NO3- conditions, and application of rac-GR24 (SL analogue) restored SR length in d10 (SL biosynthesis mutant) but not in d3, d14, and d53 (SL-responsive mutants), suggesting that higher SL signalling/levels participate in NO3--induced root elongation. D53 interacted with SPL17 and inhibited SPL17-mediated transactivation from the PIN1b promoter. Mutation of SPL14/17 and PIN1b caused insensitivity of the root elongation response to NO3- and rac-GR24 applications. Therefore, we conclude that perception of SLs by D14 leads to degradation of D53 via the proteasome system, which releases the suppression of SPL14/17-modulated transcription of PIN1b, resulting in root elongation under NO3- supply.