Role of Chitinase and Sormatin Accumulation in the Resistance of Sorghum Cultivars to Grain Mold

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• 作者：Louis K. Prom ; Ralph D. Waniska ; Abdourhamane I. Kollo ; William L. Rooney ; and Feliciano P. Bejosano
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2005
• 出版时间：July 13, 2005
• 年：2005
• 卷：53
• 期：14
• 页码：5565 - 5570
• 全文大小：229K
• 年卷期：v.53,no.14(July 13, 2005)
• ISSN：1520-5118

文摘

Experiments were conducted to determine the association between resistance to grain mold and theaccumulations of chitinase and sormatin. Eight sorghum lines were treated at 50% bloom withFusarium thapsinum, Curvularia lunata, a mixture of the two fungi, and a water-sprayed control. Atmaturity, percent disease severity, seed germination rates, and kernel weight were recorded. Chitinaseand sormatin content (mg/g of dry weight) were measured in seed samples taken at 30 and 50 daysafter treatment (DAT). Seed chitinase content was moderately affected by sorghum line (P = 0.10)and significantly affected by the developmental stage of the kernels (P = 0.05). Cultivars Sureno,98LB650, and 98LB723 exhibited larger negative changes in chitinase content at 50 DAT over water-sprayed control treatment at 30 DAT than the susceptible cultivars Dorado, RTx2536, and RTx430.In 2000, significant negative correlations were observed for percent disease severity and chitinasecontent at 30 DAT, seed germination and sormatin content at 50 DAT, and between seed germinationand kernel weight. There also was a significant positive correlation between germination and chitinasecontent at 30 DAT. No association between disease severity and changes in chitinase content at 50DAT was observed. Sormatin content also was significantly affected by the stage of kerneldevelopment. Sorghum cultivars inoculated with fungal pathogens responded differently as indicatedby the significant sorghum line × treatment interaction for sormatin content in 2000. In both years,larger increases in sormatin content over the water-sprayed control treatments were observed onmoderately susceptible to susceptible cultivars such as 98LB650, 98LB723, 98LB789, RTx430, andRTx2536 than on Sureno. Except for percent disease severity and germination, there was no significantassociation among all of the other parameters measured in 2001. The results of this study did notclearly demonstrate a strong association between resistance to grain mold and the accumulation ofsormatin and chitinase. Thus, there is the possibility that certain moderately resistant to resistantsorghum cultivars, such as Sureno, may employ other strategies to eschew or restrict fungal invasioneither before or after physiological maturity.Keywords: Fusarium thapsinum; Curvularia lunata; antifungal proteins