PHYSIOLOGICAL EFFECTS OF RESVERATROL AND COUMARIC ACID ON TWO MAJOR GROUNDNUT PESTS AND THEIR EGG PARASITOID BEHAVIOR

Groundnut, Arachis hypogea L., is one of the plant species that synthesizes phenolic compounds, resveratrol and coumaric acid. They are induced as a defense strategy in plant in response to feeding lepidopterans. The present study investigated the role of resveratrol and coumaric acid in producing antiherbivore effects as a direct defense against two major groundnut pests, Spodoptera litura F. and Amsacta albistriga W., and in indirect defense by attracting the egg parasitoid Trichogramma chilonis Ishii under laboratory conditions. The phenolic compounds deterred the feeding of both pests and caused reduction in the larval weights in a dose‐dependent manner in leaf disk bioassays. Antioxidant mechanisms of larvae fed with these phenols were measured by estimating the activities of superoxide dismutase (SOD), ascorbate peroxidase (APOX), and catalase (CAT). Enzyme activities increased significantly in experimental larvae, more so in resveratrol‐treated than in coumaric acid treated larvae. Feeding larvae with resveratrol and coumaric acid resulted in enhanced activities of detoxifying enzymes, carboxyl esterase (EST), and glutathione‐S‐transferase (GST) in the midgut tissues of both species, indicating the toxic nature of these compounds. Trichogramma chilonis was more attracted toward coumaric acid treatments in Y‐olfactometer tests than to resveratrol. This study contributes to the understanding of the roles of resveratrol and coumaric acid in direct as well as indirect defense, we infer a possible utilization of these compounds in alternate measures of groundnut pest control in future.     

Sec16 defines endoplasmic reticulum exit sites and is required for secretory cargo export in mammalian cells

The selective export of proteins and lipids from the endoplasmic reticulum (ER) is mediated by the coat protein complex II (COPII) that assembles onto the ER membrane. In higher eukaryotes, COPII proteins assemble at discrete sites on the membrane known as ER exit sites (ERES). Here, we identify Sec16 as the protein that defines ERES in mammalian cells. Sec16 localizes to ERES independent of Sec23/24 and Sec13/31. Overexpression, and to a lesser extent, small interfering RNA depletion of Sec16, both inhibit ER-to-Golgi transport suggesting that Sec16 is required in stoichiometric amounts. Sar1 activity is required to maintain the localization of Sec16 at discrete locations on the ER membrane, probably through preventing its dissociation. Our data suggest that Sar1-GTP-dependent assembly of Sec16 on the ER membrane forms an organized scaffold defining an ERES.     

Induction of phenolic acids and metals in Arachis hypogaea L. plants due to feeding of three lepidopteran pests

The feeding of lepidopteran pests, Amsacta albistriga W., Aproaerema modicella D. and Spilosoma obliqua W., caused feeding stress in the Arachis hypogaea L. plants. As a common defensive response, the plant exhibited variations in the primary and secondary metabolic contents. Groundnut plant antioxidative enzymes such as peroxidase, superoxide dismutase, polyphenol oxidase, catalase and phenyl ammonia lyase exhibited alterations to confer resistance against the pest. Phenolic compounds, namely coumaric acid, chlorogenic acid, resveratrol, epicatechin, ferulic acid and caffeic acid, showed active defensive role in groundnut plant against the pest feeding through their significant presence in Fourier transform infrared spectroscopy, high-performance liquid chromatography and gas chromatography studies. Changes in metal contents like iron, magnesium, zinc, potassium and calcium were also reported through atomic absorption studies, indicating their defensive role against the biotic stress caused on groundnut by the three lepidopteran pests. The present study can further assist in recognizing the importance of these specific phenolic acids and metals of groundnut in its pest management.