UV-B辐射增强对链格孢菌(Alternaria alternata)生长、生理及致病力的影响

研究UV-B辐射增强对灯盏花(Erigeron breviscapus)叶斑病致病菌—链格孢菌(Alternaria alternata)的生长、生理及其致病力的影响,并探讨链格孢菌对UV-B辐射的响应机制。结果表明,UV-B辐射增强可延缓链格孢菌的生长,导致菌丝生长率、产孢量、纤维素酶活性及可溶性蛋白含量均显著降低(p0.05),链格孢菌的致病力显著下降(p0.05)。同一UV-B辐射强度下,20～60min的辐射处理对链格孢菌的生长、生理及致病力的影响没有显著性差异(p0.05)。链格孢菌表现出形态学和生理生化方面的UV-B适应机制,来减轻UV-B辐射的损伤。经UV-B辐射处理后的病菌积累较多黑色素,菌落颜色加深,菌丝分布更加致密,菌丝干重显著增加(p0.05);并且,链格孢菌的过氧化氢酶(CAT)活性显著升高(p0.05)。

Effects of enhanced UV-B radiation on growth, physiology and pathogenicity of Alternaria alternata

Effects of enhanced UV-B radiation on growth, physiology and pathogenicity of the pathogenic fungus Alternaria alternata (Fr.) Keissler of the leaf spot of Erigeron breviscapus (Vant.) Hand. Mazz., and response mechanisms of A. alternata to enhanced UV-B radiation were studied. The results showed that supplemental UV-B radiation resulted in slow growth, significant decrease in mycelial growth rate, sporulation quantity, cellulase activity and soluble protein content of A.alternata (p<0.05), and significant decrease of pathogenicity of A. alternate (p<0.05). Under the same intensity of UV-B radiation, difference in the effects of radiation time of 20~60 min on growth, physiology and pathogenicity of A. alternata were not observed (p>0.05). A. alternata had adaptive mechanisms of morphology, physiology and biochemistry to alleviate UV-B injury. Treatment of UV-B radiation resulted in melanin accumulation, darker colony color, more dense distribution of hypha, and significant increase in hyphal dry weight of A. alternata (p<0.05); moreover, CAT activity of A. alternata significantly increased (p<0.05).