College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China; Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fujian Agriculture and Forestry University, Fuzhou, China.
College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China.
Plant Physiol Biochem. 2021 Aug;165:36-46. doi: 10.1016/j.plaphy.2021.05.010. Epub 2021 May 19.
The rapid accumulation of lignin in the cell wall is one of important immune defense mechanism in response to adversity stress in plants. In this study, we found that the enlargement of the root tubers of Rehmannia glutinosa (R. glutinosa) is arrested under consecutive monoculture stress, and this process is accompanied by abnormal accumulation of lignin. Meanwhile, the function of key catalytic enzyme genes in lignin biosynthetic pathway under consecutive monoculture stress was systematically analyzed, of which roles of core genes were validated using reverse genetics. We elucidated that an abnormal deposition of lignin in R. glutinosa roots, induced by consecutive monoculture stress, and arrested the enlargement of root tubers. Additionally, by manipulating the key catalytic enzyme gene RgCCR6, we were able to alter lignin content of roots of R. glutinosa, thereby affecting tuber enlargement. We speculate that cell lignification is an important defense strategy in resistance against consecutive monoculture stress, but the overreacted defense hindered the normal enlargement of root tubers. The findings provide new insights for effectively improving yield reductions of root crops subjected to environmental stress.
细胞壁中木质素的快速积累是植物应对逆境的重要免疫防御机制之一。在这项研究中，我们发现地黄（Rehmannia glutinosa）的块根在连续单一种植胁迫下生长受阻，并且这一过程伴随着木质素的异常积累。同时，我们系统地分析了木质素生物合成途径中关键催化酶基因在连续单一种植胁迫下的功能，并用反向遗传学验证了核心基因的作用。我们阐明了连续单一种植胁迫诱导的地黄根中木质素的异常沉积，从而阻止了块根的增大。此外，通过操纵关键催化酶基因 RgCCR6，我们能够改变地黄根中的木质素含量，从而影响块根的增大。我们推测细胞木质化是抵抗连续单一种植胁迫的重要防御策略，但过度的防御反应阻碍了根状茎的正常增大。这些发现为有效提高根类作物在环境胁迫下的减产提供了新的思路。
