Proteomic analysis of soybean defense response induced by cotton worm (prodenia litura, fabricius) feeding

Ten protein spots that are changed in abundance in response to cotton worm feeding were identified by Two-dimensional gel electrophoresis (2-DE). A total of 11 unique proteins from these spots were identified by MALDI-TOF MS. The mRNA and protein relative expression levels of most changed proteins were up-regulated. These proteins were mainly involved in physiological processes, including active oxygen removal, defense signal transduction, and metabolism regulation.This is the first proteomic analysis of the soybean defense response induced by cotton worm. The differentially expressed proteins could work together to play a major role in the induced defense response. PAL and SAMS were up-regulated at both the protein and mRNA levels. These genes can be strongest candidates for further functional research.As an important economic crop, soybean provides significant sources of fatty acids, proteins, vitamins, minerals and other nutrients for humans and animals, and it also has nonfood uses, such as in the production of industrial feedstocks and combustible fuels [1,2]. However, insect pests can adversely affect the yield and quality of soybean. Cotton worm is one of the main insect pests of soybean in southern China [3,4]. Therefore, improvement in resistance to cotton worm is one of the main soybean breeding objectives.During the process of evolution, plants have acquired defense mechanisms that confer protection from predation by herbivores. Two modes of resistance to herbivores exist: constitutive resistance, which is expressed independent of an attack; and induced resistance, which is activated only after the plant is attacked or otherwise injured [5]. Compared with constitutive resistance, induced resistance may be more durable and compromises plant fitness less by either decreasing further herbivore damage or increasing plant tolerance to herbivory [6]. Induced responses that lead to increased resistance against herbivores have been reported for over 100 species o