Dobrikova Anelia G, Yotsova Ekaterina K, Börner Andreas, Landjeva Svetlana P, Apostolova Emilia L
Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
Plant Physiol Biochem. 2017 May;114:10-18. doi: 10.1016/j.plaphy.2017.02.015. Epub 2017 Feb 20.
Тhe sensitivity to cadmium (Cd) stress of two near-isogenic wheat lines with differences at the Rht-B1 locus, Rht-B1a (tall wild type, encoding DELLA proteins) and Rht-B1c (dwarf mutant, encoding modified DELLA proteins), was investigated. The effects of 100 μM CdCl on plant growth, pigment content and functional activity of the photosynthetic apparatus of wheat seedlings grown on a nutrient solution were evaluated through a combination of PAM chlorophyll fluorescence, oxygen evolution, oxidation-reduction kinetics of P700 and 77 K fluorescence. The results showed that the wheat mutant (Rht-B1c) was more tolerant to Cd stress compared to the wild type (Rht-B1a), as evidenced by the lower reductions in plant growth and pigment content, lower inhibition of photosystem I (PSI) and photosystem II (PSII) photochemistry and of the oxygen evolution measured with Clark-type and Joliot-type electrodes. Furthermore, the enhanced Cd tolerance was accompanied by increased Cd accumulation within mutant plant tissues. The molecular mechanisms through which the Rht-B1c mutation improves plant tolerance to Cd stress involve structural alterations in the mutant photosynthetic membranes leading to better protection of the Mn cluster of oxygen-evolving complex and increased capacity for PSI cyclic electron transport, protecting photochemical activity of the photosynthetic apparatus under stress. This study suggests a role for the Rht-B1c-encoded DELLA proteins in protective mechanisms and tolerance of the photosynthetic apparatus in wheat plants exposed to heavy metals stress.
研究了在Rht - B1位点存在差异的两个近等基因小麦品系Rht - B1a（高杆野生型，编码DELLA蛋白）和Rht - B1c（矮杆突变体，编码修饰的DELLA蛋白）对镉（Cd）胁迫的敏感性。通过PAM叶绿素荧光、放氧量、P700氧化还原动力学和77K荧光相结合的方法，评估了100μM CdCl₂对在营养液中生长的小麦幼苗的植物生长、色素含量和光合机构功能活性的影响。结果表明，与野生型（Rht - B1a）相比，小麦突变体（Rht - B1c）对Cd胁迫更具耐受性，这表现为植物生长和色素含量的降低幅度较小，用Clark型和Joliot型电极测量的光系统I（PSI）和光系统II（PSII）光化学以及放氧量的抑制作用较低。此外，突变体植物组织中Cd积累增加伴随着Cd耐受性增强。Rht - B1c突变提高植物对Cd胁迫耐受性的分子机制涉及突变光合膜的结构改变，从而更好地保护放氧复合体的Mn簇，并增加PSI循环电子传递能力，在胁迫下保护光合机构的光化学活性。本研究表明，Rht - B1c编码的DELLA蛋白在遭受重金属胁迫的小麦植株光合机构的保护机制和耐受性中发挥作用。
