Plant Cell Reports

, Volume 26, Issue 4, pp 395–405

Cloning and functional expression of the gene encoding an inhibitor against Aspergillus flavus α-amylase, a novel seed lectin from Lablab purpureus (Dolichos lablab)

  • Young-Hwa Kim
  • Charles P. Woloshuk
  • Eun Hee Cho
  • Jung Myung Bae
  • Young-Sun Song
  • Gyung Hye Huh
Cell Biology and Morphogenesis

DOI: 10.1007/s00299-006-0250-2

Cite this article as:
Kim, YH., Woloshuk, C.P., Cho, E.H. et al. Plant Cell Rep (2007) 26: 395. doi:10.1007/s00299-006-0250-2

Abstract

Maize is one of the more important agricultural crops in the world and, under certain conditions, prone to attack from pathogenic fungi. One of these, Aspergillus flavus, produces toxic and carcinogenic metabolites, called aflatoxins, as byproducts of its infection of maize kernels. The α-amylase of A. flavus is known to promote aflatoxin production in the endosperm of these infected kernels, and a 36-kDa protein from the Lablab purpureus, denoted AILP, has been shown to inhibit α-amylase production and the growth of A. flavus. Here, we report the isolation of six full-length labAI genes encoding AILP and a detailed analysis of the activities of the encoded proteins. Each of the six labAI genes encoded sequences of 274 amino acids, with the deduced amino acid sequences showing approximately 95–99% identity. The sequences are similar to those of lectin members of a legume lectin–arcelin–α-amylase inhibitor family reported to function in plant resistance to insect pests. The labAI genes did not show any of the structures characteristic of conserved structures identified in α-amylase inhibitors to date. The recombinant proteins of labAI-1 and labAI-2 agglutinated human red blood cells and inhibited A. flavus α-amylase in a manner similar to that shown by AILP. These data indicate that labAI genes are a new class of lectin members in legume seeds and that their proteins have both lectin and α-amylase inhibitor activity. These results are a valuable contribution to our knowledge of plant–pathogen interactions and will be applicable for developing protocols aimed at controlling A. flavus infection.

Keywords

labAILablab purpureusα-Amylase inhibitor activityLectin activityAspergillus flavusAflatoxin

Abbreviations

α-AI

α-Amylase inhibitor

AIL

α-Amylase inhibitor-like protein

AILP

α-Amylase inhibitor from Lablab purpureus

AP

Adaptor primer

AOX

Alcohol oxidase

BMGY

Buffered glycerol complex medium

BMMY

Buffered methanol complex medium

GSP

Gene-specific primer

PHA

Phytohemagglutinin

TI

Trypsin inhibitor

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Young-Hwa Kim
    • 1
    • 2
  • Charles P. Woloshuk
    • 3
  • Eun Hee Cho
    • 2
  • Jung Myung Bae
    • 4
  • Young-Sun Song
    • 1
  • Gyung Hye Huh
    • 2
  1. 1.School of Food and Life Science, BPRCInje UniversityObangdongKorea
  2. 2.Department of Biomedical InformaticsInje UniversityObandgongKorea
  3. 3.Department of Botany and Plant PathologyPurdue UniversityWest LafayetteUSA
  4. 4.School of Life Sciences and BiotechnologyKorea UniversitySeoulKorea