Departamento de Bioquimica e Biologia Molecular, Universidade Federal do Ceara, Fortaleza, CE, CEP, Brazil.
J Agric Food Chem. 2010 Apr 14;58(7):4090-6. doi: 10.1021/jf903254b.
This study reports on the antifungal activity of Dgui, a ConA-like lectin from Dioclea guianensis seeds. Dgui inhibited conidial germination but not mycelial growth of Colletotrichum gloeosporioides. The lectins ConA and ConM from Canavalia ensiformis and Canavalia maritima, respectively, share high levels of amino acid sequence similarity (>84%) with Dgui and have the same specificity toward glucose/mannose but had no effect on the fungus. Fluorescence microscopy showed that both Dgui and ConM bind to C. gloeosporioides ungerminated conidia. However, Dgui did not bind to C. gloeosporioides germinated conidia and germ tubes and was not inhibitory to mycelial growth. Because only Dgui inhibited germination of the fungus, C. gloeosporioides conidia might have surface-specific germination targets recognized by Dgui but not by its homologues, ConM and ConA. Therefore, Dgui is a candidate for biotechnological approaches for improving the resistance of various nutritionally and commercially important crops that are affected by C. gloeosporioides.
本研究报告了来自 Dioclea guianensis 种子的 ConA 样凝集素 Dgui 的抗真菌活性。Dgui 抑制分生孢子的萌发，但不抑制 Colletotrichum gloeosporioides 的菌丝生长。凝集素 ConA 和 ConM 分别来自 Canavalia ensiformis 和 Canavalia maritima，与 Dgui 具有高度的氨基酸序列相似性（>84%），对葡萄糖/甘露糖具有相同的特异性，但对真菌没有影响。荧光显微镜观察表明，Dgui 和 ConM 均与未萌发的 C. gloeosporioides 分生孢子结合。然而，Dgui 不与 C. gloeosporioides 萌发的分生孢子和芽管结合，也不抑制菌丝生长。由于只有 Dgui 抑制真菌的萌发，因此 C. gloeosporioides 分生孢子可能具有表面特异性的萌发靶标，Dgui 可以识别这些靶标，但它的同源物 ConM 和 ConA 则不能。因此，Dgui 是生物技术方法的候选物，可用于提高各种受 C. gloeosporioides 影响的营养和商业重要作物的抗性。
