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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #234990
Title: Physiological, nutritional and biochemical bases of corn resistance to foliage-feeding fall armyworm (Lepidoptera:noctuidae)

Author
item CHEN, YIGEN - UNIV. OF GEORGIA
item Ni, Xinzhi
item BUNTIN, G. DAVID - UNIV. OF GEORGIA

Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2009
Publication Date: 2/19/2009
Citation: Chen, Y., Ni, X., Buntin, G. 2009. Physiological, nutritional and biochemical bases of corn resistance to foliage-feeding fall armyworm (Lepidoptera:noctuidae). Journal of Chemical Ecology 35:297-306.

Interpretive Summary: Three corn germplasm lines were examined for fall armyworm resistance. Nutritional and biochemical properties of these corn germplasm lines were examined to categorize resistance mechanisms to the fall armyworm feeding. Physiological changes in photosynthetic rates were also examined in an attempt to explain nutritional and biochemical dynamics among corn germplasm lines and between insect-damaged and un-damaged corn plants within a germplasm line. Results indicated that fall armyworm larvae survived better and developed faster in susceptible Ab24E than in resistant FAW7050 and Mp708. The three corn germplasm lines differed in resistance mechanisms to the fall armyworm. The observed patterns of resistance was probably a collective results of N:C ratio and defensive proteins. The susceptibility of Ab24E to the fall armyworm was due to high N:C and low induced defensive compounds in response to fall armyworm feeding, while the resistance of FAW7050 results from elevated defensive proteins following insect feeding. The elevated protein content in resistant germplasm lines Mp708 and FAW7050 following fall armyworm feeding injury was probably due to greater conversion rate of photosynthates to protein. Greater photosynthetic capacity in Mp708 and FAW7050 also led to higher amino acid and glucose contents in these two resistant lines. Neither amino acid nor lipoxygenase 3 played a critical role in corn resistance to the fall armyworm. However, highly inducible peroxidase activity may be an indicator of susceptibility of corn seedlings to fall armyworm feeding injury.

Technical Abstract: Three corn (Zea mays) germplasm lines, Ab24E (susceptible control), Mp708 (resistant control), and a locally selected partial inbred line FAW7050 (resistant), were examined for Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) resistance. Nutritional [i.e., total protein, amino acids, glucose, total non-structural carbohydrates (TNC), protein to TNC ratios (P:C)] and biochemical (i.e., peroxidase and lipoxygenase 3) properties of corn lines were examined to categorize resistance mechanisms to S. frugiperda. Physiological changes in photosynthetic rates were also examined in an attempt to explain nutritional and biochemical dynamics among corn germplasm lines and between insect-damaged and un-damaged corn plants within a germplasm line. Results indicated that S. frugiperda larvae survived better and developed faster in susceptible Ab24E than in resistant FAW7050 and Mp708. The three corn germplasm lines differed in resistance mechanisms to S. frugiperda, and the observed patterns of resistance was probably a collective results of P:C and defensive proteins. That is, the susceptibility of Ab24E to S. frugiperda was due to high P:C and low induced defensive compounds in response to herbivory; the resistance of FAW7050 results from elevated defensive proteins of this line following herbivory; and low P:C and elevated defensive proteins in Mp708 contributed to its resistance to S. frugiperda. The elevated protein amounts in resistant germplasms Mp708 and FAW7050 following S. frugiperda injury was probably due to greater conversion of photosynthates to these compounds due to greater photosynthetic rates in these entries. Greater photosynthetic capacity in Mp708 and FAW7050 also lead to higher amino acid and glucose contents in these two lines. Neither amino acid nor lipoxygenase 3 played a critical role in corn resistance to S. frugiperda. However, high inducibility of peroxidase activity may be an indicator of susceptibility as observed elsewhere.