Front Plant Sci：浙大周伟军团队揭示紫茎甘蓝在干旱胁迫下的生理表型

今天介绍的是浙江大学周伟军团队在Frontiers in Plant Science上发表的研究论文《Purple stem Brassica napus exhibits higher photosynthetic efficiency, antioxidant potential and anthocyanin biosynthesis related genes expression against drought stress》。

紫茎甘蓝 (B.napus)花青素含量高，是一种颜色独特的表型。花青素是一种天然存在的植物色素，具有抗氧化活性，在植物抵御非生物和生物胁迫中发挥着重要作用。

作者以绿茎(GS)和紫茎(PS)甘蓝为材料，研究了水培条件下干旱对植株的影响。研究结果表明，干旱过程中花青素积累的主要作用是可以提高甘蓝植株的抗氧化能力和抗逆性。

本研究的结果表明，干旱显著抑制了植物的生长，表现为两种基因型的甘蓝生物量积累减少，而GS基因型的生物量积累明显下降。在干旱胁迫下，GS基因型的光合特性降低更为明显，但PS基因型却表现出更好的生理表型。

在胁迫条件下，两个品种均表现出活性氧(ROS)和丙二醛(MDA)积累增加，以及较高水平的抗氧化酶活性。在干旱条件下，GS基因型植株的叶绿体受到明显的变形伤害，表现为类囊体质膜和基粒结构变形，且淀粉粒较少，质体小球较大。此外，在干旱胁迫期间，PS基因型的花青素生物合成基因和抗氧化酶的表达水平最高，与GS基因型相比，PS基因型具有更高的抗逆性。

根据这些结果，可以得出结论，GS基因比PS基因对干旱胁迫更敏感。此外，本研究还为利用花青素生物合成或调控基因开发耐逆作物的植物生物学家提供了实用指导。

Purple-stem Brassica napus (B. napus) is a phenotype with unique color because of its high anthocyanins content. Anthocyanins are naturally occurring plant pigments that have antioxidants activity and play important role in plant defense against abiotic and biotic stresses. In the present study, drought induced effects on plants were investigated in hydroponically grown seedlings of green stem (GS) and purple stem (PS) genotypes of B. napus. The results of this study showed that the major function of anthocyanins accumulation during drought was to enhance the antioxidant capability and stress tolerance in B. napus plants. Our results showed that drought significantly inhibited the plant growth in terms of decreased biomass accumulation in both genotypes, although marked decline was observed in GS genotype. The reduction in photosynthetic attributes was more noticeable in the GS genotype, whereas the PS genotype showed better performance under drought stress. Under stressful conditions, both the genotype showed excessive accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA), as well as higher levels of antioxidant enzymes activities. Under drought conditions, the GS genotype showed apparent damages on chloroplast deformation like in thylakoid membrane and grana structural distortion and fewer starch grains and bigger plastoglobuli. Moreover, during drought stress, the PS genotype exhibited maximum expression levels of anthocyanins biosynthesis genes and antioxidant enzymes accompanied by higher stress tolerance relative to GS genotype. Based on these findings, it can be concluded that GS genotype found more sensitive to drought stress than the PS genotype. Furthermore this research paper also provides practical guidance for plant biologists who are developing stress-tolerant crops by using anthocyanin biosynthesis or regulatory genes.Copyright © 2022 Chen, Miao, Ayyaz, Hannan, Huang, Ulhassan, Zhou, Islam, Hong, Farooq and Zhou.

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