Department of Plant Physiology, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Universitätsstrasse 30, 95447, Bayreuth, Germany.
School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, LE12 5RD, UK.
Sci Rep. 2017 Jun 16;7(1):3693. doi: 10.1038/s41598-017-03540-z.
Metal tolerance is often a result of metal storage or distribution. Thus, with the goal of advancing the molecular understanding of such metal homeostatic mechanisms, natural variation of metal tolerance in Arabidopsis thaliana was investigated. Substantial variation exists in tolerance of excess copper (Cu), zinc (Zn) and cadmium (Cd). Two accessions, Col-0 and Bur-0, and a recombinant inbred line (RIL) population derived from these parents were chosen for further analysis of Cd and Zn tolerance variation, which is evident at different plant ages in various experimental systems and appears to be genetically linked. Three QTLs, explaining in total nearly 50% of the variation in Cd tolerance, were mapped. The one obvious candidate gene in the mapped intervals, HMA3, is unlikely to contribute to the variation. In order to identify additional candidate genes the Cd responses of Col-0 and Bur-0 were compared at the transcriptome level. The sustained common Cd response of the two accessions was dominated by processes implicated in plant pathogen defense. Accession-specific differences suggested a more efficient activation of acclimative responses as underlying the higher Cd tolerance of Bur-0. The second hypothesis derived from the physiological characterization of the accessions is a reduced Cd accumulation in Bur-0.
金属耐受性通常是金属储存或分布的结果。因此，为了深入了解这种金属稳态机制的分子基础，研究了拟南芥金属耐受性的自然变异。过量铜（Cu）、锌（Zn）和镉（Cd）的耐受性存在很大差异。选择 Col-0 和 Bur-0 两个品系以及由这两个亲本衍生的重组自交系（RIL）群体，进一步分析 Cd 和 Zn 耐受性的变异，这在不同的实验系统中不同的植物年龄阶段都很明显，并且似乎与遗传有关。定位了三个解释 Cd 耐受性变异的 QTL，共解释了近 50%的变异。映射区间内唯一明显的候选基因 HMA3 不太可能导致变异。为了鉴定其他候选基因，比较了 Col-0 和 Bur-0 在转录组水平上对 Cd 的反应。两个品系对 Cd 的持续共同反应主要涉及到植物病原体防御过程。品系特异性差异表明，Bur-0 中适应性反应的激活更为有效，这是其对 Cd 耐受性更高的基础。从品系的生理特性得出的第二个假设是 Bur-0 中 Cd 积累减少。
