Soybean (Glycine max L.) is the world’s most widely grown seed legume. One of the most important pests that decrease seeds quality and reduce yield of soybean crops is the southern green stink bug (Nezara viridula). However, insect damage triggers accumulation of defensive compounds, such as protease inhibitors (PI), isoflavonoids, and reactive oxygen species to stop stink bug feeding, which are regulated by jasmonic acid (JA). The aim of this study was to identify and characterize the role of LOX isoforms in the modulation of chemical defences in growing seeds of field-grown soybean as response to N. viridula attack. Stink bug attack increased LOX 1 and LOX 2 expression, and activities of LOX 1 and LOX 3 isoenzymes in developing soybean seeds. In addition, stink bug damage and MeJA application induced expression and activity of both cysteine PI and trypsin PI in developing soybean seeds, suggesting that herbivory induced JA in soybean seeds. Moreover, the high PI levels in attacked seeds decreased cysteine proteases and α-amylases activities in the gut of stink bugs that fed on field-grown soybean. In this study we demonstrated that LOX isoforms of seeds are concomitantly induced with JA-regulated PIs by stink bug attack, and these PIs inhibit the activity of insect digestive enzymes. To our knowledge no study before has investigated the participation of LOX in modulating JA-regulated defences against stink bugs in seeds of field-grown soybean, and the impact of soybean PIs on α-amylase activity in the gut of N.viridula
Audience Take Away:
- They can induce soybean defenses to decrease stink bug damage.
- Learning the mechanism of plant responses to herbivory will help to manipulate plant responses against insect pests
- Studying soybean seeds responses to herbivory can be used a model of plant responses against herbivory and help to study similar responses in other crops.