Sahoo Manas Ranjan, DasGupta Madhumita, Kole Paresh C, Bhat Jayant S, Mukherjee Archana
Department of Crop Improvement, Horticulture and Agricultural Botany, Institute of Agriculture, Visva-Bharati, Sriniketan 731236, West Bengal, India.
Mycopathologia. 2007 Apr;163(4):241-8. doi: 10.1007/s11046-007-9000-4. Epub 2007 Apr 3.
Assessment of the differential expression of antioxidative enzymes and their isozymes, was done in 30 day-old ex vitro raised plants of three highly resistant (DP-25, Jhankri and Duradim) and one highly susceptible (N-118) genotypes of taro [Colocasia esculenta (L.) Schott]. Antioxidative enzymes were assayed in the ex vitro plants, 7 days after inoculation with the spores (15,000 spores ml(-1) water) of Phytophthora colocasiae Raciborski to induce taro leaf blight disease. Uninoculated ex vitro plants in each genotype were used as control. The activity of superoxide dismutase (SOD) and guaiacol peroxidase (GPX) increased under induced blight condition when compared with control. Increase in antioxidative enzymes was more (67-92%) in the resistant genotypes than that (21-29%) of the susceptible genotype. The zymograms of SOD and GPX in the resistant genotypes, with pathogenic infection, showed increased activity for anodal isoform of SOD and increased expression and/or induction of either POX 1 or POX 2 isoforms of GPX. In susceptible genotype, expression of the above isoforms was faint for SOD and nearly absent for GPX under both blight free and induced blight conditions. Induction and/or increased activity of particular isoform of SOD and GPX against infection of Phytophthora colocasiae in the resistant genotypes studied led to the apparent conclusion of linkage of isozyme expression with blight resistance in taro. This might be an important criterion in breeding of taro for Phytophthora leaf blight resistance.
对三种高度抗病（DP - 25、Jhankri和Duradim）和一种高度感病（N - 118）的芋头[Colocasia esculenta (L.) Schott]基因型的30日龄离体培养植株进行了抗氧化酶及其同工酶差异表达的评估。在用芋疫霉（Phytophthora colocasiae Raciborski）孢子（15,000个孢子/毫升水）接种以诱发芋头叶枯病7天后，对离体培养植株中的抗氧化酶进行了测定。每种基因型未接种的离体培养植株用作对照。与对照相比，在诱发叶枯病条件下，超氧化物歧化酶（SOD）和愈创木酚过氧化物酶（GPX）的活性增加。抗病基因型中抗氧化酶的增加幅度（67 - 92%）大于感病基因型（21 - 29%）。在抗病基因型中，感染病原菌后，SOD和GPX的酶谱显示SOD阳极同工型的活性增加，GPX的POX 1或POX 2同工型的表达和/或诱导增加。在感病基因型中，在无叶枯病和诱发叶枯病条件下，上述同工型的SOD表达微弱，GPX几乎不表达。在所研究的抗病基因型中，特定的SOD和GPX同工型针对芋疫霉感染的诱导和/或活性增加，导致得出同工酶表达与芋头抗叶枯病相关的明显结论。这可能是芋头抗芋疫霉叶枯病育种中的一个重要标准。
