采后BTH处理对甘薯块根生理品质和黑斑病抗性的影响

Effects of benzothiadiazole treatment on physiological quality and disease resistance to Ceratocystis fimbriata in postharvest sweet potato roots

中文关键词:  甘薯块根  苯并噻二唑  长喙壳菌  生理品质  抗病性

英文关键词:Sweet potato roots  Benzothiadiazole  Ceratocystis fimbriata Ellis et Halsted  Physiological quality  Quality  Disease resistance

中文摘要:

      本试验以“心香”甘薯块根为材料，研究9.0 mmol/L苯并噻二唑（Benzothiadiazole，BTH）处理诱导甘薯抗黑斑病以及延缓生理品质下降的效果。甘薯块根于9.0 mmol/L BTH浸泡处理，后接种长喙壳菌，随后在28±1℃、80%~85% RH条件下贮藏25 d，每隔5 d取样，检测生理品质以及抗病相关指标。结果表明：BTH处理显著（p<0.05）抑制了病斑扩展进程，但对病原菌体外生长无直接抑制作用；BTH处理提高了苯丙氨酸解氨酶（PAL）、肉桂酸羟化酶（C4H）、过氧化物酶（POD）和4-香豆酸辅酶A连接酶（4CL）活性，促进了总酚和木质素的累积，在贮藏的第15 d时，分别较对照提高25.17%和18.43%；显著提高了几丁质酶（CHT）和β-1,3-葡聚糖酶（GLU）的活性；提高了过氧化氢（H?O?）含量和超氧阴离子（O2·-）产生速率；延缓了相对电导率的上升和丙二醛（MDA）的累积，在贮藏期间，分别较对照减少13.33%~33.70%以及12.70%~31.91%，从而维持了细胞膜完整性；抑制了淀粉的降解和可溶性糖含量的上升。综上，采后BTH处理有助于诱导甘薯块根增强对黑斑病的抗性和保持甘薯块根的生理品质。

英文摘要:

      The effects of benzothiadiazole on regulating the physiological quality and disease resistance to Ceratocystis fimbriata Ellis et Halsted in sweet potato roots(Ipomoea batatas (L.) Lam ‘Xinxiang’)were evaluated after the sweet potato roots were dipped in 9.0 mmol/L BTH for 60 min and subsequently inoculated with C. fimbriata Ellis et Halsted, and stored at 28±1 °C with 80%～85% relative humidity for 25 days. Samples were collected every 5 days to evaluate physiological quality and disease resistance–related biochemical indices. The results showed that BTH treatment significantly (p<0.05) suppressed lesion area expansion without directly antifungal activity against C. fimbriata Ellis et Halsted in vitro. The BTH treatment enhanced the activities of Phenylalanine ammonia-lyase(PAL), Cinnamate 4-hydroxylase(C4H),Peroxidase(POD), and 4-Coumarate:CoA ligase(4CL), thereby promoting the accumulation of total phenolic and lignin，which increased by 25.17% and 18.43%, respectively, compared to the control on day 15 of storage, markedly increased the activities of CHT and GLU and elevated the contents of H?O? and the production rate of superoxide anion(O2·-). BTH treatment also delayed increase in relative conductivity and the content of MDA(Malondialdehyde)，which were reduced by 13.33%–33.70% and 12.70%–31.91%, respectively, compared to the control during the entire storage period. Furthermore, it inhibited starch degradation and the excessive rise in soluble sugar content. These results suggested that BTH treatment activated multiple defense-related metabolic pathways and maintained cell wall stability, which were contributed to enhancing disease resistance of sweet potatoes roots and maintaining the physiological quality during storage.