Characterization, induction by wounding and salicylic acid, and activity against Botrytis cinerea of chitinases and β‐1,3‐glucanases of ripening grape berries |
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Authors: | JeanPaul Derckel JeanClaude Audran Bernard Haye Bernard Lambert Laurent Legendre |
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Institution: | J.‐P. Derckel, J.‐C. Audran, B. Haye, B. Lambert and L. Legendre (corresponding author, e‐mail;), Univ. of Reims Champagne‐Ardenne, Laboratory of Plant Biology and Physiology, URVVC‐EA 2069, UFR Sciences, Moulin de la Housse, B.P. 1039, F‐51687 Reims Cedex 2, France. |
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Abstract: | In order to better understand the defense strategy of grape berries ( Vitis vinifera L. cv. Pinot noir) as they mature, the activities of the defense‐related proteins, chitinase (CHV, EC 3.2.1.14) and β‐1,3‐glucanase (laminarinase, EC 3.2.1.39) were first estimated in berries at different maturation stages. Chitinase levels rose proportionally to the berry reducing sugar content, an indicator of the berry ripening degree, up to values 10 times higher than the ones seen in resting grapevine leaves. This rise in activity was due to the accumulation of two isoforms, CHV 5 and CHV 11. One more chitinase isoform, CHV 12, appeared in senescent berries. Conversely, no glucanase activity could be detected in berries at any maturation stage. Accumulation of chitinases and (β‐1,3‐glucanases could be stimulated by wounding the berry peduncle. Adding salicylic acid to the wounded berries only potentiated the wounding effect on the berry chitinase activity. The most active chitinase isoform, CHV 5, was purified to homogeneity. It represented about 40% of the total extractable protein content of a ripe berry. Its molecular mass was estimated to be 31 kDa. The peptide sequencing of four of its tryptic fragments revealed strong homologies to several class IV chitinases. Finally, it was shown to inhibit the germination of conidia of Botrytis cinerea by 50% at a concentration of 7.5 µg ml−1. |
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Keywords: | Botrytis cinerea chitinase fruit ripening β‐1 3‐glucanase grapes pathogenesis‐related (PR) protein salicylic acid Vitis vinifera wounding |
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