嫁接茄子根系分泌物变化及其对黄萎菌的影响

采用番茄为砧木嫁接茄子,经过GC-MS检测,研究了黄萎菌胁迫前后嫁接对茄子植株根系次生代谢的影响。通过比较黄萎菌胁迫前后茄子根系次生代谢物质的变化,探讨了嫁接在胁迫前后对植株根系次生代谢的调节作用,并对嫁接茄根系分泌物中丁二酸二甲酯对茄子黄萎菌及茄子种子萌发、幼苗生长的化感效应进行了研究。结果表明,黄萎菌胁迫前,嫁接影响了根系的次生代谢物质的分泌,表现为物质种类和数量的增加,各类物质相对含量改变。嫁接茄子根系分泌物中检测出9大类、66种物质,比自根茄处理多出4大类、33种物质。黄萎菌胁迫时,嫁接茄子田间表现出明显的抗病性;进一步对根系分泌物进行检测发现,嫁接茄根系分泌物中物质种类和相对含量与自根茄处理相比均有显著差别;嫁接茄根系分泌物中烃和酚醇类物质相对含量分别增加了3.25%和0.07%,苯类、茚类和脂肪酸酯类物质相对含量降低,降幅分别为2.62%、0.26%和0.07%。新出现了胺类物质,芴类物质。黄萎菌胁迫前后茄子根系次生代谢物质成分同样发生了变化。与接菌前嫁接茄子植株根系分泌物相比,接菌后嫁接处理的苯类、茚类、酚醇类和胺类物质相对含量增加,增幅分别为22.07%、1.72%、1.21%和0.34%;烃类和脂肪酸酯类物质相对含量降低了1.28%和21.75%;酮类、咔唑类和芴类物质消失。新增物质中以丁二酸二甲酯的相对含量最高,达14.38%。随后的生物检测结果显示,丁二酸二甲酯能够提高茄子田间抗病性,对黄萎菌菌丝生长起化感抑制作用,并促进了茄子种子的萌发和幼苗的生长,随着处理浓度升高作用效果增强,并在1 mmol/L处理时达到最佳作用效果。

Effect of grafting eggplant on root exudates and disease resistance under Verticillium dahliae stress

Plants synthesize a diverse array of secondary metabolites that are important for them to survive and flourish in the natural environments. The root secondary metabolites play an important role in plant microbe interactions, particularly in the plant defenses against pathogenic attacks. Verticillium dahliae the causal agent of Verticillium wilt, often attack the root of eggplants, and causes significant reductions of yield in eggplant (Solanum melongena L.) production where crop rotation is limited. Grafting is considered as an effective method to control this disease. Some wild species eggplants and resistant tomatoes are available for eggplant rootstock. After grafting, the root secondary metabolites could change to resist the V. dahliae stress. Therefore, the regulation of grafting to root secondary metabolism may be one of the disease resistance metabolisms for grafting. Using tomato as rootstock, the effects of grafted eggplant on root secondary metabolites were studied by GC-MS in this paper. The modulation of grafting to root secondary metabolism was discussed by comparing the root secondary metabolites with and without Verticillium dahliae stress. The allelopathic effects of butanedioic acid, dimethyl ester to Verticillium wilt (Verticillium dahllae), seed germination and seedling growth of eggplant in grafted treatment were determined using simulative method. The results showed that grafting affected the secondary metabolism of eggplant roots without V. dahliae stress. The categories and amounts of root secondary metabolites increased, and their relative contents in grafted treatment changed compared with non-grafted treatment. Nine categories and 66 substances in grafted treatment were detected, in which were 4 categories and 33 substances were determined in grafted treatment than in non-grafted treatment. Under V. dahliae stress, the grafted treatment exhibited strong disease resistance. Amang the root secondary metabolites, the relative contents of hydrocarbon and phenol and acohol in grafted treatment were increased by 3.25% and 0.07% compared with non-grafted treatment, while benzene, indene and fatty acid ester were decreased by 2.62%, 0.26% and 0.07%, respectively. Amine was detected only in grafted treatment, but not fluorine. For grafted treatment, after inoculating V. dahliae, the contents of benzene, indene, phenol, acohol and amine were increased by 22.07%, 1.72%, 1.21% and 0.34%, respectively, but hydrocarbon and fatty acid ester decreased by 1.28% and 21.75%, respectively. There was no ketone, carbazole and fluorine in grafted treatment under V. dahliae stress. Butanedioic acid, dimethyl ester presented only in grafted treatment after inoculating V. dahliae, and was the most distinct. Butanedioic acid, dimethyl ester enhanced the disease resistance of eggplant and inhibited the mycelium growth of V. dahliae. And it improved the seed germination and seedling growth of eggplants. At the concentration of 1 mmol/L, the improvements were the best. It indicates that grafting can affect the composition of eggplants by using tomato as rootstock.