Calzadilla Pablo Ignacio, Signorelli Santiago, Escaray Francisco Jose, Menéndez Ana Bernardina, Monza Jorge, Ruiz Oscar Adolfo, Maiale Santiago Javier
UB1, Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús, UNSAM-CONICET, Chascomús, Argentina.
Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay; School of Plant Biology and the UWA Institute of Agriculture, University of Western Australia, Perth, Australia.
Plant Sci. 2016 Sep;250:59-68. doi: 10.1016/j.plantsci.2016.06.003. Epub 2016 Jun 3.
Lotus species are important forage legumes due to their high nutritional value and adaptability to marginal conditions. However, the dry matter production and regrowth rate of cultivable Lotus spp. is drastically reduced during colder seasons. In this work, we evaluated the chilling response of Lotus japonicus ecotypes MG-1 and MG-20. No significant increases were observed in reactive oxygen species and nitric oxide production or in lipid peroxidation, although a chilling-induced redox imbalance was suggested through NADPH/NADP(+) ratio alterations. Antioxidant enzyme catalase, ascorbate peroxidase, and superoxide dismutase activities were also measured. Superoxide dismutase, in particular the chloroplastic isoform, showed different activity for different ecotypes and treatments. Stress-induced photoinhibition also differentially influenced both ecotypes, with MG-1 more affected than MG-20. Data showed that the D2 PSII subunit was more affected than D1 after 1 d of low temperature exposure, although its protein levels recovered over the course of the experiment. Interestingly, D2 recovery was accompanied by improvements in photosynthetic parameters (Asat and Fv/Fm) and the NADPH/NADP(+) ratio. Our results suggest that the D2 protein is involved in the acclimation response of L. japonicus to low temperature. This may provide a deeper insight into the chilling tolerance mechanisms of the Lotus genus.
由于其高营养价值和对边缘条件的适应性，莲属植物是重要的饲用豆科植物。然而，可栽培莲属植物的干物质产量和再生率在较冷季节会大幅降低。在这项研究中，我们评估了日本莲生态型MG-1和MG-20的冷害响应。尽管通过NADPH/NADP(+)比值变化表明存在冷害诱导的氧化还原失衡，但活性氧、一氧化氮的产生以及脂质过氧化均未观察到显著增加。我们还测定了抗氧化酶过氧化氢酶、抗坏血酸过氧化物酶和超氧化物歧化酶的活性。超氧化物歧化酶，尤其是叶绿体同工型，对不同生态型和处理表现出不同的活性。胁迫诱导的光抑制对两种生态型也有不同影响，MG-1比MG-20受影响更大。数据表明，低温处理1天后，D2 PSII亚基比D1受影响更大，尽管其蛋白质水平在实验过程中有所恢复。有趣的是，D2的恢复伴随着光合参数（Asat和Fv/Fm）以及NADPH/NADP(+)比值的改善。我们的结果表明，D2蛋白参与了日本莲对低温的适应性反应。这可能为深入了解莲属植物的耐寒机制提供线索。
