Scott Ian M, McDowell Tim, Renaud Justin B, Krolikowski Sophie W, Chen Ling, Dhaubhadel Sangeeta
Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON N5V 4T3, Canada.
Insects. 2022 Apr 5;13(4):356. doi: 10.3390/insects13040356.
Soybean aphid () is a major soybean () herbivore pest in many soybean growing regions. High numbers of aphids on soybean can cause severe reductions in yield. The management of soybean aphids includes monitoring, insecticide applications when required, and the use of resistant cultivars. Soybean aphid-resistant soybean varieties are associated with genes that confer one or more categories of resistance to soybean aphids, including antibiosis (affects survival, growth, and fecundity), antixenosis (affects behaviour such as feeding), and tolerance (plant can withstand greater damage without economic loss). The genetic resistance of soybean to several herbivores has been associated with isoflavonoid phytoalexins; however, this correlation has not been observed in soybean varieties commonly grown in southern Ontario, Canada. Isoflavonoids in the leaves of 18 cultivars in the early growth stage were analyzed by HPLC and the concentration by fresh weight was used to rate the potential resistance to aphids. Greenhouse and growth cabinet trials determined that the cultivars with greater resistance to aphids were Harosoy 63 and OAC Avatar. The most susceptible cultivar was Maple Arrow, whereas Pagoda and Conrad were more tolerant to aphid feeding damage. Overall, there was a low correlation between the number of aphids per leaf, feeding damage, and leaf isoflavonoid levels. Metabolite profiling by high-resolution LC-MS determined that the most resistant cultivar had on average lower levels of certain free amino acids (Met, Tyr, and His) relative to the most susceptible cultivar. This suggests that within the tested cultivars, nutritional quality stimulates aphid feeding more than isoflavonoids negatively affect aphid feeding or growth. These findings provide a better understanding of soybean host plant resistance and suggest ways to improve soybean resistance to aphid feeding through the breeding or metabolic engineering of leaf metabolites.
大豆蚜（Aphis glycines）是许多大豆种植区的主要大豆食草害虫。大豆上大量的蚜虫会导致产量严重下降。大豆蚜的管理包括监测、必要时施用杀虫剂以及使用抗性品种。抗大豆蚜的大豆品种与赋予对大豆蚜一种或多种抗性的基因相关，包括抗生性（影响存活、生长和繁殖力）、抗虫性（影响取食等行为）和耐受性（植物能够承受更大的损害而不造成经济损失）。大豆对几种食草动物的遗传抗性与异黄酮植保素有关；然而，在加拿大安大略省南部普遍种植的大豆品种中未观察到这种相关性。通过高效液相色谱法分析了18个品种早期生长阶段叶片中的异黄酮，并以鲜重浓度来评估对蚜虫的潜在抗性。温室和生长箱试验确定，对蚜虫抗性较强的品种是哈罗索伊63（Harosoy 63）和奥AC阿凡达（OAC Avatar）。最易感的品种是枫箭（Maple Arrow），而宝塔（Pagoda）和康拉德（Conrad）对蚜虫取食损害更具耐受性。总体而言，每片叶上的蚜虫数量、取食损害和叶片异黄酮水平之间的相关性较低。通过高分辨率液相色谱 - 质谱联用进行的代谢物谱分析确定，相对于最易感品种，抗性最强的品种某些游离氨基酸（蛋氨酸、酪氨酸和组氨酸）的平均水平较低。这表明在测试的品种中，营养质量对蚜虫取食的刺激作用大于异黄酮对蚜虫取食或生长的负面影响。这些发现有助于更好地理解大豆寄主植物抗性，并提出通过叶片代谢物的育种或代谢工程来提高大豆对蚜虫取食抗性的方法。
