ABSTRACT

Phosphate deficiency is a stress factor often limiting crop growth and development. The aim of this study was to determine the expression of microRNAs (miRNAs) in response to long-term phosphate stress in red clover populations in field conditions. The sensitivity of six red clover populations to phosphate stress was determined in a three-year field experiment. The results revealed that the declines in hay yield and quality under phosphate stress were less pronounced for two populations compared to the other four. Molecular analysis revealed significant down-regulation (miRNA156, miRNA171 and miRNA2111) and up-regulation (miRNA399) in the phosphate stress-tolerant populations exposed to phosphate stress, but no changes were observed in the non-phosphate stress-tolerant populations. The results collectively suggest that miRNA156, miRNA171, miRNA399 and miRNA2111 could be responsible for tolerance to phosphate limited conditions in some red clovers. These miRNAs could be used for the development of red clover plants that are tolerant of phosphate-deficient soils. In addition, since phosphate stress-tolerant populations should require less phosphate fertiliser, they would have the potential to mitigate environmental pollution from farming soils with elevated phosphate levels.

摘要

磷酸盐缺乏是一种压力因素，通常会限制作物的生长和发育。本研究的目的是确定在田间条件下红三叶草种群中长期磷酸盐胁迫下 microRNA (miRNA) 的表达。在为期三年的田间试验中确定了六种红三叶草种群对磷酸盐胁迫的敏感性。结果表明，与其他四个种群相比，在磷酸盐胁迫下，两个种群的干草产量和质量下降不太明显。分子分析显示暴露于磷酸盐胁迫的磷酸盐胁迫耐受人群中显着下调（miRNA156、miRNA171 和 miRNA2111）和上调（miRNA399），但在非磷酸盐胁迫耐受人群中未观察到变化。结果共同表明 miRNA156、miRNA171、miRNA399 和 miRNA2111 可能是一些红三叶草对磷酸盐限制条件的耐受性的原因。这些 miRNA 可用于培育耐受缺磷土壤的红三叶草植物。此外，由于耐磷酸盐胁迫的种群应该需要较少的磷肥，它们将有可能减轻磷酸盐含量升高的农业土壤对环境的污染。