Characterization of a stress responsive proteinase inhibitor gene with positive effect in improving drought resistance in rice

Abstract

A full-length cDNA gene, designated Oryza sativa chymotrypsin inhibitor-like 1 (OCPI1), was characterized in rice. The predicted protein of OCPI1 shows very high sequence identity to reported chymotrypsin inhibitors from various plant species. Northern-blot analysis showed that the expression of OCPI1 was strongly induced by dehydration stresses and abscisic acid (ABA). The expression of beta-glucuronidase (GUS) reporter gene under the control of OCPI1 promoter transformed into rice was strongly induced by drought and salt stresses. Interestingly, strong dehydration stress-induced GUS activity was also detected in the transgenic rice containing the reverse sequence of OCPI1 promoter fused to GUS gene, suggesting of a bidirectional transcriptional activity in the OCPI1 promoter. OCPI1 gene was over-expressed in japonica cv. Zhonghua 11 and transgenic plants containing single copy of transgene were tested for drought resistance at reproductive stage. The positive transgenic plants (OCPI1 was over-expressed) had significantly higher grain yield and seed setting rate than the wild type and the negative transgenic control (no over-expression of the transgene) under the severe drought stress conditions, whereas the potential yield of transgenic plants under normal growth conditions was not affected. Chymotrypsin-inhibitor activity assay showed that the crude protein of the positive transgenic plants had stronger inhibitory activity than the negative control. Transgenic plants had less decrease of total proteins than the wild type under drought stress. Taken together, these data indicate that OCPI1 might potentially be useful in the genetic improvement of drought resistance in rice.

Características de tolerância à seca em genótipos de uma coleção nuclear de arroz de terras altas

“…A busca por cultivares de arroz de terras altas tolerantes à seca é reconhecida como a estratégia mais eficiente para aliviar a insegurança alimentar causada pela escassez de água (Huang et al, 2007). Nesse sentido, a avaliação dessa característica em uma coleção nuclear temática para tolerância à seca, que necessariamente apresenta grande variação genética para a característica, tem grande relevância.…”

Physiological, Morphological and Molecular Mechanisms for Drought Tolerance in Rice

“…OCPI1 (Oryza sativa chymotrypsin inhibitor-like 1), a stress responsive proteinase inhibitor gene Huang et al, 2007 …”

Genomic and cDNA Cloning, Expression, Purification, and Characterization of Chymotrypsin-Trypsin Inhibitor from Winged Bean Seeds

“…1) Plant protease inhibitors are also involved in the responses to various biotic and abiotic stresses, e.g., pathogen invasion, wounding, and environmental stresses. 2,3) Proteinase inhibitors are common in plants and have drawn attention as possible transgenes for insect defense in crops. They are of particular interest because they are generally the product of a single gene and inhibit proteolytic enzymes of animal and fungal origin, but rarely of plant origin, and therefore are thought to act as protective agents.…”