小肽Ospep5对水稻耐镉性的影响

Effects of small peptide Ospep5 on cadmium tolerance in rice

镉(Cd)胁迫是植物面临的主要重金属胁迫之一,对植物的生长和发育产生严重的影响。尽管已有研究表明植物小肽具有缓解胁迫的作用,但水稻中镉毒害的研究很少。在前期研究中,通过翻译组、转录组和蛋白质组鉴定了一系列水稻小肽,其中发现Ospep5可以显著地提高水稻的耐盐性。本研究以日本晴野生型、日本晴过表达Ospep5-OX和日本晴CRISPR/Cas9突变体ospep5-3作为水稻试验材料,研究Ospep5对镉胁迫下水稻幼苗生长的影响。试验结果表明:500μmol L^(–1)CdCl_(2)处理显著抑制了水稻幼苗的形态生长和叶绿素含量,同时超氧化物歧化酶(SOD)、脯氨酸(Pro)含量、丙二醛(MDA)含量和镉离子含量显著提高。与单独的镉胁迫相比,外源施加Ospep5后,可以有效缓解镉胁迫对水稻幼苗的形态生长的抑制,显著提高超氧化物歧化酶(SOD)活力,同时显著降低丙二醛(MDA)含量、脯氨酸(Pro)含量和镉离子含量,并且能够促进耐镉基因(OsHMA2、OsHMA3、OsCAL1)的表达。总之,Ospep5通过调节水稻幼苗各种生理生化反应以及调控耐镉基因表达的方式,最终提高水稻幼苗对镉胁迫的耐受性。

Cadmium(Cd)stress is one of the major heavy metal stresses which causes serious impacts on plant growth and development.Although studies have shown that plant small peptides have a mitigating effect on stress,research on their tolerance to cadmium toxicity in rice is limited.In previous studies,a few peptides were identified through translatome,transcriptome,and proteome analysis,among which Ospep5 was found to significantly improve salt tolerance in rice.In this study,the effects of Ospep5 on the growth of rice seedlings under cadmium stress were investigated using the japonica cultivar Nipponbare,Ospep5 overexpressing line Ospep5-OX,and the CRISPR/Cas9 mutant ospep5-3 as the experimental materials.The results showed that 500μmol L–1 CdCl2 significantly inhibited the morphological growth and chlorophyll content of rice seedlings,while the activities of superoxide dismutase(SOD),contents of proline(Pro),malondialdehyde(MDA),and cadmium ion content were significantly increased.Compared to cadmium stress alone,exogenous application of synthetic Ospep5 effectively alleviated the inhibition of cadmium stress on the morphological growth of rice seedlings.Furthermore,SOD activity was significantly increased,and MDA content,Pro content,and cadmium ion content were significantly reduced.And the relative expression level of cadmium tolerance genes(OsHMA2,OsHMA3,OsCAL1)were upregulated.In conclusion,Ospep5 improves the tolerance of rice seedlings to cadmium stress by regulating various physiological and biochemical reactions and the expression of cadmium tolerance genes.