Molecular cloning, characterization and gene expression of a water deficiency and chilling induced proteinase inhibitor I gene family from sweet potato (Ipomoea batatas Lam.) leaves
Resource
Plant Science 165 (1): 191-203
Journal
Plant Science
Pages
191-203
Date Issued
2003
Date
2003
Author(s)
Wang, Hui-Yi
Huang, Ya-Chen
Chen, Shih-Fung
Yeh, Kai-Wun
Abstract
A 7-kDa-proteinase inhibitor, designated SPLTI (Sweet Potato Leaf Trypsin Inhibitor) was partially purified from sweet potato (Ipomoea batatas Lam.) leaves under water deficiency. The N-terminal amino acid sequence was determined and used to design two overlap degenerate primers for isolation of the SPLTI gene. Two full-length cDNA clones encoding proteinase inhibitor I (PI-I), designated SPLTI-a and SPLTI-b, were isolated. Both SPLTI-a and SPLTI-b are 98% identical to each other in both levels of nucleotide and amino acid sequence. Different from most of PI-Is that exhibit chymotrypsin-inhibitory activity, SPLTI from sweet potato and recombinant SPLTI-a overexpressed in Escherichia coli showed mainly trypsin-inhibitory activity. Furthermore, site-directed mutagenesis analysis of an Arg46-Glu47 motif of SPLTI-a, based on amino acid sequence alignment with other PI-Is, indicated that Arg46-Glu47 of SPLTI is a novel reactive site for PI-I family conferring the trypsin-specific inhibitory activity. Using SPLTI-a as a probe, we found that SPLTI gene exhibited a leaf-specific expression pattern. Additionally, this was the first report that the SPLTI genes were up-regulated by water deficiency and chilling as well as osmoticant treatments in the PI-I family in plants. As other PIs, the SPLTI transcripts were induced by wounding and also by exogenous applications of abscisic acid and methyl jasmonate; however, accumulation of the wound-induced transcripts were restricted locally in the injured leaves, but not systemically. These distinct expression patterns provided a new insight to the regulation of PI-I gene family in response to environmental stresses. Our results suggested that SPLTI could participate in defense systems against invasions of insects or bacteria as other PI-Is. Moreover, it may play a role against environmental stresses through regulation of endogenous proteolytic activities during leaf development. © 2003 Elsevier Science Ireland Ltd. All rights reserved.
SDGs
File(s)![Thumbnail Image]()
Loading...
Name
19.pdf
Size
666.06 KB
Format
Adobe PDF
Checksum
(MD5):d966b34f95bc9b140bab567fa8043cae