A novel antifungal protein from seeds of Sesbania virgata (Cav.) Pers. (Leguminosae-Faboideae)

Pg Praxedes,Lo Dias,Rab Pessoni,Jk Zerlin

doi:10.1590/s1519-69842011000400013

Abstract

A novel antifungal protein with a molecular mass around 50 kDa was purified from seeds of Sesbania virgata (Cav.) Pers. using ammonium sulfate fractionation followed by gel filtration on a Sephadex G-75 Superfine (Sigma) column and reverse-phase high performance liquid chromatography on a C8 column. The protein, designated FP1-A, with a novel N-terminal sequence AMVHSPGG(S)FS(P), showed growth inhibitory activity of filamentous fungi Aspergillus niger, Cladosporium cladosporioides, Colletotrichum gloeosporioides and Fusarium solani.

Highlights

Fungi, bacteria, viruses and nematodes continually challenge plants growing under natural environmental conditions, but few pathogens succeed in invading plant tissues
Purification of P65% was performed by gel filtration column chromatography on SephadexTM G-75 Superfine column and the eluted fractions were monitored for their ability to inhibit the radial growth of A. niger, as well as their OD at 280 nm
Further purification of F1 and F2 was done by using reverse-phase high-performance liquid chromatography (RP-High-performance liquid chromatography (HPLC)) (Figure 2)

Summary

Introduction

Bacteria, viruses and nematodes continually challenge plants growing under natural environmental conditions, but few pathogens succeed in invading plant tissues. Plants do not have an immune system, they have evolved a variety of potent defensive mechanisms, including the synthesis of low-molecular-weight compounds, proteins and peptides with antifungal activity. The constitutive expression of plant antimicrobial proteins in the peripheral cells of seeds, flower organs, leaves and tubers is consistent with their role in the first-line defence of vulnerable tissues (Broekaert et al, 1995). This inference is strengthened by the rapid induction of certain antimicrobial peptides after plants are infected by microorganisms or injured (Hancock and Lehrer, 1998). Enhance the chances of seedling survival and plant reproduction (Diz et al, 2003)

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Conclusion