State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Plant Sci. 2022 Sep;322:111371. doi: 10.1016/j.plantsci.2022.111371. Epub 2022 Jul 7.
Auxin is involved in stress responses of plants, such as phosphorus (P) deficiency in rice. Studies on whether auxin participates in cell-wall inorganic phosphorous (Pi) reutilization in Pi-starved rice are scarce. This study explored the mechanisms underlying auxin-facilitated cell-wall Pi-reutilization in rice roots. Pi deficiency rapidly induced auxin accumulation in roots; exogenous auxin [α-naphthaleneacetic acid (NAA), a permeable analog of auxin] elevated soluble Pi content in roots and shoots by increasing pectin content by enhancing activity of pectin methylesterase, and upregulating the transcript level of PHOSPHORUS-TRANSPORTER-2, such that more Pi was translocated to the shoot. Irrespective of the Pi status, exogenous auxin induced nitric oxide (NO) and ethylene production, while exogenous sodium nitroprusside (an NO donor) and 1-aminocyclopropane-1-carboxylic acid (a precursor of ethylene) had no effect on auxin content, suggesting that auxin may act upstream of NO and ethylene. The beneficial effect of NAA in increasing soluble Pi content in roots and shoots disappeared when 2-(4-carboxyphenyl)- 4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (a scavenger of NO) or aminoethoxyvinylglycine (an inhibitor of ethylene) were applied, suggesting that auxin facilitates cell-wall Pi-reutilization in a NO-ethylene-dependent manner in Pi-deficient rice. Our study results suggest auxin application as an effective agronomic practice for improving plant Pi nutrition in P-deficient conditions.
生长素参与植物的应激反应，例如水稻缺磷。关于生长素是否参与磷饥饿水稻细胞壁无机磷（Pi）再利用的研究很少。本研究探讨了生长素促进水稻根系细胞壁 Pi 再利用的机制。缺磷迅速诱导根系生长素积累；外源性生长素[α-萘乙酸（NAA），生长素的可渗透类似物]通过增强果胶甲酯酶的活性增加果胶含量，从而提高根和地上部的可溶性 Pi 含量，并上调 PHOSPHORUS-TRANSPORTER-2 的转录水平，使更多的 Pi 被转运到地上部。无论 Pi 状态如何，外源性生长素都诱导一氧化氮（NO）和乙烯的产生，而外源性硝普钠（NO 供体）和 1-氨基环丙烷-1-羧酸（乙烯前体）对生长素含量没有影响，这表明生长素可能作用于 NO 和乙烯的上游。当应用 2-(4-羧基苯基)-4,4,5,5-四甲基咪唑啉-1-氧-3-氧化物（NO 清除剂）或氨基乙氧基乙烯基甘氨酸（乙烯抑制剂）时，NAA 增加根和地上部可溶性 Pi 含量的有益效果消失，这表明生长素以依赖于 NO-乙烯的方式促进磷饥饿水稻细胞壁 Pi 再利用。我们的研究结果表明，生长素的应用是一种有效的农业实践，可以改善磷缺乏条件下植物的磷营养。
