de Menezes Henrique D, Massola Nelson S, Flint Stephan D, Silva Geraldo J, Bachmann Luciano, Rangel Drauzio E N, Braga Gilberto U L
Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil.
Photochem Photobiol. 2015 Mar-Apr;91(2):397-402. doi: 10.1111/php.12410. Epub 2015 Jan 15.
Light conditions can influence fungal development. Some spectral wavebands can induce conidial production, whereas others can kill the conidia, reducing the population size and limiting dispersal. The plant pathogenic fungus Colletotrichum acutatum causes anthracnose in several crops. During the asexual stage on the host plant, Colletototrichum produces acervuli with abundant mucilage-embedded conidia. These conidia are responsible for fungal dispersal and host infection. This study examined the effect of visible light during C. acutatum growth on the production of conidia and mucilage and also on the UV tolerance of these conidia. Conidial tolerance to an environmentally realistic UV irradiance was determined both in conidia surrounded by mucilage on sporulating colonies and in conidial suspension. Exposures to visible light during fungal growth increased production of conidia and mucilage as well as conidial tolerance to UV. Colonies exposed to light produced 1.7 times more conidia than colonies grown in continuous darkness. The UV tolerances of conidia produced under light were at least two times higher than conidia produced in the dark. Conidia embedded in the mucilage on sporulating colonies were more tolerant of UV than conidia in suspension that were washed free of mucilage. Conidial tolerance to UV radiation varied among five selected isolates.
光照条件会影响真菌的发育。一些光谱波段可诱导分生孢子的产生，而其他波段则可杀死分生孢子，从而减少种群数量并限制传播。植物病原真菌尖孢炭疽菌可在多种作物上引发炭疽病。在寄主植物上的无性阶段，尖孢炭疽菌产生具大量黏液包埋分生孢子的分生孢子盘。这些分生孢子负责真菌的传播和寄主感染。本研究考察了可见光在尖孢炭疽菌生长过程中对分生孢子和黏液产生的影响，以及对这些分生孢子紫外线耐受性的影响。在产孢菌落上被黏液包围的分生孢子以及分生孢子悬液中，测定了分生孢子对环境现实紫外线辐照度的耐受性。真菌生长期间暴露于可见光下会增加分生孢子和黏液的产生以及分生孢子对紫外线的耐受性。暴露于光照下的菌落产生的分生孢子比在持续黑暗中生长的菌落多1.7倍。在光照下产生的分生孢子的紫外线耐受性至少比在黑暗中产生的分生孢子高两倍。产孢菌落上黏液包埋的分生孢子比洗去黏液的悬浮分生孢子对紫外线更具耐受性。五个选定分离株的分生孢子对紫外线辐射的耐受性各不相同。
