Analysis of the Mechanisms for Soilborne Plant Disease Development using REMI-Mutants of Fusarium oxysporum

大约20个尖孢镰刀菌的致病突变体。SP.从2500个转化子中筛选出粘着菌(甘蓝黄化病原菌FOC)和番茄枯萎病病原菌(FOL)，证明FOC的致病力缺失突变体REMI10已将pCNS43插入基因组。被pCSN43插入中断的基因被挽救，该基因似乎编码了一种天冬氨酸蛋白酶。我们将该基因命名为fap1。FOC的FAPL干扰物对甘蓝的致病力与FOC平衡，表明FAP1对FOC的致病性不起作用。用REMI10处理甘蓝根部，可降低FOC引起的黄化发病率。这表明Remi 10具有生防活性。在荧光显微镜下观察了表达绿色荧光蛋白(GFP)的REMI10(EGFP-REMI10)的行为，发现EGFP-REMI10通过角质层进入甘蓝根部的速度慢于FOC，即使在接种后14d，EGFP-REMI10也没有通过内胚层进入木质部。用pCSN43标记的基因编码321个氨基酸的蛋白，命名为foir1，同源性搜索表明它与非洲爪哇的氯离子电导调节蛋白部分相似，提示FOIR1是一种跨膜蛋白。虽然FOIR1的作用尚未确定，但它可能参与了FOL的致病作用，因为FOIR1基因缺失的突变体对番茄的致病力降低。

About 20 pathogenicity mutants of Fusarium oxysporum ff. sp. conglutinans (cabbage yellows pathogen ; FOC) and lycopersici (tomato wilt pathogen ; FOL) were selected from about 2500 transformants generated by restriction enzyme-mediated integration (REMI) mutagenesis.REMI10, a pathogenicity-deficient mutant of FOC, was proved that a copy of pCNS43 was inserted into the genome. The gene disrupted by the insertion of pCSN43 was rescued and the gene seemed to encode an aspartic proteinase. We designated the gene fap1. fapl disruptants of FOC carried pathogenicity to cabbage equilibrant with FOC, showed that FAP1 is not responsible to FOC for pathogenicity. Pretreatment of cabbage root with REMI10 reduced the disease incidence of yellows caused by FOC. This suggested that REMI 10 carried biocontrol activity. Behavior of green fluorescence protein (GFP)-expressing REMI10 (EGFP-REMI10) was observed under fluorescence microscope and we could see that EGFP-REMI10 penetrate into cabbage root through cuticle slower than FOC and EGFP-REMI10 did not go through the endodermis to the xylem even 14 days after inoculation.r-120, a reduced pathogenicity mutant of FOL, was also proved that a copy of pCNS43 was inserted into the genome. The gene tagged in the mutant with pCSN43 was predicted to encode a protein of 321 amino acids and designated foir1, Homology search showed its partial similarity to a chloride conductance regulatory protein of Xenopus laevis, suggesting that FOIR1 is a transmembrane protein. Although the role of FOIR1 has never been identified, it may participate to the pathogenicity in FOL, because FOIR1 deficient mutants of FOL reproduced reduced pathogenicity on tomato.