硅和稻瘟病菌接种对水稻植株有机酸含量的影响

Influence of silicon application and Magnaporthe oryzae infection on organic acids contents in rice plants

以抗病性不同的一对水稻近等基因系——感病CO39和抗病C101LAC(Pi-1)为实验材料,在水培条件下研究了施硅和稻瘟病接菌对水稻根系和叶片抗性物质有机酸含量的影响,揭示硅提高水稻对稻瘟病抗性的机理。结果表明:接菌条件下硅处理显著降低了2个基因型材料的叶片反丁烯二酸、柠檬酸的含量,而增加了叶片中草酸、顺丁烯二酸的含量;加硅显著降低接菌后第3天的CO39叶片酒石酸含量,但增加了C101LAC(Pi-1)接菌后第7天的叶片酒石酸含量;硅处理还显著增加了根系中苹果酸和草酸的含量;各种有机酸在水稻植株体内的分布也不尽相同,如柠檬酸主要分布在叶片中,苹果酸主要分布在根系中,顺丁烯二酸、反丁烯二酸、酒石酸和草酸在叶片和根系中都有分布。研究表明,硅可能通过影响植株体内的有机酸代谢而增强稻瘟病的抗性。

Two rice near-isogenic lines （NILs） with different resistance to blast, i.e. CO39 （susceptible） and CIO1LAC（Pi-1） （resistant）, were used to investigate the impacts of silicon application on organic acid content of rice plants infected by Magnaporthe oryzae, the pathogen of rice blast. In infected leaves, Si application significantly increased oxalic acid and maleic acid contents and reduced fumaric acid and citric acid contents of both rice lines. Malic acid and oxa- lic acid contents in roots of infected plants for both lines were also increased by Si application. Tartaric acid content in the infected leaves was significantly reduced by Si application in CO39 on the third day after the pathogen infection, but it increased in C101LAC （Pi-1） on the seventh day after the infection. The distribution of organic acids in both lines of rice plants varied ： Citric acid was mainly distributed in leaves, malic acid in roots, and maleic acid, fumaric acid, tartaric acid and oxalic acid in both leaves and roots. These results suggest that Si application influences plant metabolism and thus enhances the resistance to blast under M. oryzae-infected conditions.