Li Cuiling, Liu Guangchao, Geng Xiaoyu, He Chunmei, Quan Taiyong, Hayashi Ken-Ichiro, De Smet Ive, Robert Hélène S, Ding Zhaojun, Yang Zhong-Bao
The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Science, Shandong University (Qingdao), Qingdao, 266237, P.R. China.
School of Life Science, Qingdao Agricultural University, Qingdao, 266109, P.R. China.
Plant J. 2021 Oct;108(1):55-66. doi: 10.1111/tpj.15424. Epub 2021 Jul 30.
Aluminium (Al) stress is a major limiting factor for worldwide crop production in acid soils. In Arabidopsis thaliana, the TAA1-dependent local auxin biosynthesis in the root-apex transition zone (TZ), the major perception site for Al toxicity, is crucial for the Al-induced root-growth inhibition, while the mechanism underlying Al-regulated auxin accumulation in the TZ is not fully understood. In the present study, the role of auxin transport in Al-induced local auxin accumulation in the TZ and root-growth inhibition was investigated. Our results showed that PIN-FORMED (PIN) proteins such as PIN1, PIN3, PIN4 and PIN7 and AUX1/LAX proteins such as AUX1, LAX1 and LAX2 were all ectopically up-regulated in the root-apex TZ in response to Al stress and coordinately regulated local auxin accumulation in the TZ and root-growth inhibition. The ectopic up-regulation of PIN1 in the TZ under Al stress was regulated by both ethylene and auxin, with auxin signalling acting downstream of ethylene. Al-induced PIN1 up-regulation and auxin accumulation in the root-apex TZ was also regulated by the calossin-like protein BIG. Together, our results provide insight into how Al stress induces local auxin accumulation in the TZ and root-growth inhibition through the local regulation of auxin transport.
铝（Al）胁迫是酸性土壤中全球作物生产的主要限制因素。在拟南芥中，根尖过渡区（TZ）中依赖TAA1的局部生长素生物合成是铝毒性的主要感知部位，对于铝诱导的根生长抑制至关重要，而铝调节TZ中生长素积累的潜在机制尚不完全清楚。在本研究中，研究了生长素运输在铝诱导的TZ中局部生长素积累和根生长抑制中的作用。我们的结果表明，PIN-FORMED（PIN）蛋白如PIN1、PIN3、PIN4和PIN7以及AUX1/LAX蛋白如AUX1、LAX1和LAX2在根尖TZ中均异位上调以响应铝胁迫，并协同调节TZ中局部生长素积累和根生长抑制。铝胁迫下TZ中PIN1的异位上调受乙烯和生长素共同调节，生长素信号传导作用于乙烯下游。铝诱导的根尖TZ中PIN1上调和生长素积累也受类钙调蛋白BIG调节。总之，我们的结果为铝胁迫如何通过局部调节生长素运输诱导TZ中局部生长素积累和根生长抑制提供了见解。
