HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hossain, M. A. Articles by Sen, S. K. Search for Related Content PubMed Articles by Hossain, M. A. Articles by Sen, S. K. Agricola Articles by Hossain, M. A. Articles by Sen, S. K. Related Collections Insect Resistance Gene Expression Cell Biology & Molecular Genetics

Transgenic Expression of Onion Leaf Lectin Gene in Indian Mustard Offers Protection against Aphid Colonization

IIT-BREF Biotek, Indian Institute of Technology, Kharagpur 721302, India

View larger version (24K): [in a new window]   Fig. 1. Schematic representation of the T-DNA region of (A) pCAMBIA-ACA which carried the Allium cepa agglutinin (ACA) gene; and (B) pCAMBIA-ASAL::ACA which carried the fusion lectin (ASAL::ACA) gene; 2x35S, doubly enhanced CaMV35S promoter; hypt II, hygromycin resistance gene; Nos, nopaline synthase transcriptional terminator; RB, right border; LB, left border. ASAL, Allium sativum leaf agglutinin.

View larger version (53K): [in a new window]   Fig. 2. Amino acid sequences corresponding to mature peptides of Galanthus nivalis agglutinin (GNA), Allium sativum leaf agglutinin (ASAL), and Allium cepa agglutinin (ACA). The sequences were aligned using Biowire Jellyfish Version 3.0 www.biowire.com). Underlined amino acids indicate the mannose-binding domain (QXDXNXXXY), and the shaded regions show identical amino acids among the three sequences.

View larger version (24K): [in a new window]   Fig. 3. Insect bioassay test for sensitivity of four lectins when present with the artificial diet. (A) Different concentration levels of lectin (10–50 µg mL–1) were offered to 16 insects and surivivability was monitored after 2 d. (B) Specific activity of different lectins causing mortality to the insects monitored every day for 5 d, when 20 µg mL–1 of different lectins was mixed with artificial diet.

View larger version (52K): [in a new window]   Fig. 4. Western blot analysis of total protein from transformed B. juncea plants using Allium cepa agglutinin (ACA) specific antibody. (A) Expression of ACA gene product amongst transgenic lines (T0). Lane 1, untransformed plant (–ve); lane 2, ACA peptide as positive control (+ve); lanes 3–9, transgenic plant lines ACA#2, 16, 12, 8, 14, 18, and 4, respectively. (B) Expression of fusion lectin amongst transgenic lines (T0) ASAL::ACA. Lanes 1–7, transformed plants with ASAL::ACA#2, 4, 5, 8, 9, 7, 11, respectively; lane 8, untransformed plant as negative control (–ve); lane 9, ACA peptide as positive control (+ve). ASAL, Allium sativum leaf agglutinin.

View larger version (47K): [in a new window]   Fig. 5. Southern blot analysis of some of the primary transgenic plant lines. (A) Transgenic plant lines with Allium cepa agglutinin (ACA) gene. Lane 1, untransformed plant as negative control (–ve); lanes 2–8, transgenic lines ACA#7, 6, 8, 16, 2, 10, 12, respectively; lane 9, plasmid DNA (pCAMBIA-ACA) as positive control (+ve). (B) Transgenic plant lines with ASAL::ACA fused lectin gene; lane 1, untransformed plant as negative control (–ve); lanes 2–9 transgenic lines ASAL::ACA# 2, 4, 5, 7, 6, 8, 9, 11, respectively; and lane 10, plasmid DNA (pCAMBIA- ASAL::ACA) as positive control (+ve). ASAL, Allium sativum leaf agglutinin.

View larger version (15K): [in a new window]   Fig. 6. Adverse effects on the survivability and fecundity of insects were observed when the insects colonized on transgenic plants containing the Allium cepa agglutinin (ACA) peptide. First instar nymphs of aphids were placed on young transgenic and control (untransformed) plants. (A) After 8 d, the survivability of the insects was monitored. (B) After 14 d, the total number of insects (adults and nymphs) was estimated to judge the fecundity of the insects as the result of feeding on transgenic plants expressing the lectin peptide.

View larger version (106K): [in a new window]   Fig. 7. The figure demonstrates accumulation of aphid population after 40 d on a transgenic plant ACA #8 expressing Allium cepa agglutinin (ACA) lectin peptide versus an untransformed plant. On the 40th day, the flowering twig shows (A) only a few aphids are present in the transgenic ACA #8; (B) the twig is fully infested with aphids on the untransformed control plant parts.

View larger version (16K): [in a new window]   Fig. 8. The normal flow of increase of population of aphids with time was severely affected when observed after 40 d on the transgenic plant line expressing ACA lectin peptide, when compared to the increase of aphid population after 40 d on the untransformed plant. The figure documents that the number of aphids colonizing on the transgenic plant, ACA# 8 had shown an initial increase until the d 20, but ceased to increase further. On the contrary, the number of aphids infesting the untransformed plant has shown rapid increase with passage of time. The ( line indicates insects on untransformed PCR7 plant and the line indicates insects on transgenic ACA#8 plant.