蚕豆根系分泌物中氨基酸含量与枯萎病的关系

通过田间试验研究不同品种蚕豆枯萎病病情指数的差异,并通过水培试验鉴定蚕豆根系分泌物中氨基酸组分并测定氨基酸的含量,分析各氨基酸组分与蚕豆枯萎病病情指数的相关性。结果表明:根系分泌物中氨基酸总量随着蚕豆枯萎病抗性的降低而升高。感病品种和中抗品种中检出15种氨基酸,而抗病品种中检出14种,组氨酸只存在于中抗品种中,脯氨酸仅在感病品种中检测到,3个蚕豆品种根系分泌物中均未检出精氨酸。丝氨酸(Ser)、蛋氨酸(Met)和赖氨酸(Lys)与枯萎病病指呈负相关关系,以Ser的相关系数最高,其他13种氨基酸含量与蚕豆枯萎病的病情指数呈正相关。蚕豆根系分泌物中Ser、Met和Lys含量及Ser/Gly、Ser/Ala比值高能抑制枯萎病的发生与发展,而天门冬氨酸(Asp)、苏氨酸(Thr)、甘氨酸(Gly)、丙氨酸(Ala)、缬氨酸(Val)、酪氨酸(Tyr)、苯丙氨酸(Phe)含量高时能促进枯萎病的发生。不同蚕豆品种根系分泌的氨基酸含量与组分的差异是影响蚕豆对枯萎病抗性差异的重要原因之一。

Relationship of free amino acids in root exudates with wilt disease (Fusarium Oxysporum) of faba bean

With a field plot experiment, differences in fusarium wilt disease index between three faba bean cultivars different in resistance to the disease were studied, and with a nutrient solution culture experiment, contents of free amino acids in root exudates of the plants were determined and their relationships with incidence of fusarium wilt were analyzed. Results show that the resistance to fusarium wilt of all the three cultivars of faba bean cultivars increased with increasing total content of free amino acids in the root exudates Of the fifteen kinds of amino acids detected in the root exudates of faba beans histidine was specific to resistant faba bean cultivars while proline was to susceptible cultivars. Arginine was not found in the root exudates of all the three faba bean cultivars. Disease index was negatively related to the contents of serine, methionine and lysine, with serine being the most significant, but fusarium wilt disease index was positively related to the contents of the other thirteen amino acids. High contents of serine, methionine and lysine and high Ser/Gly and Ser/Ala ratios were found inhibiting occurrence and development of faba bean fusarium wilt, while high contents of Aspartic, threonine, glycine, alanine, valine, tyrosine and phenylalanine were inducing occurrence of faba bean fusarium wilt. Faba beans different in variety vary in content and composition of free amino acids in their root exudates, which is one of the main reasons why the beans are different in resistance to fusarium wilt.