Botrytis caroliniana

by Cliff Bueno de Mesquita

I have finished analyzing data from an experiment I did looking at how adding plant litter (dead leaves) affects microbial communities in unvegetated soils. Since microbial growth in unvegetated soils can be limited by carbon, and plant leaves contain lots of carbon,  we expected to see changes in microbial communities as different microbes increase in growth to decompose the leaves. Besides that, leaves also harbor their own microbial communities, which also get added to soil when they fall. Botrytis caroliniana (Figure 1) is a species of fungus that was abundant in plant litter but also varied among plant species. B. caroliniana was especially abundant in the leaves of the mountain sorrel plant Oxyria digyna and less abundant in the grass Deschampsia cespitosa and the cushion plant Silene acaulis. ​

Figure 1. Botrytis caroliniana growth on potato dextrose agar after 3 days (A) and 18 days (B). Photo from Li et al. 2012.

Botrytis is a relatively well studied fungal genus with 22 described species, which typically cause disease in plants (Williamson et al. 2007). Botrytis species can be both biotrophs (eating living material) or necrotrophs (eating dead tissues). Several books have been written about the genus, focusing on their negative effects on important crop species (Elad et al. 2007). For example, the species Botrytis cinerea is reported to cause gray mold disease on 200 crop species, including cabbage, lettuce, broccoli, beans, grapes, strawberries, raspberries, and blackberries (Figure 2, Williamson et al. 2007). Botrytis caroliniana gets its name because it was first isolated from blackberry in South Carolina (Li et al. 2012). It has also been reported to cause gray mold disease on strawberries in North Carolina (Fernández-Ortuño et al. 2012). It is closely related to Botrytis fabiopsis and Botrytis galanthina, which cause gray mold disease in broad bean and snowdrop plants (Li et al. 2012). ​

Figure 2. Gray mold disease caused by Botrytis cinerea on strawberries (A) and raspberries (B). Photo from Williamson et al. 2007.

​Clearly, fungi in this genus are pathogens that can have major impacts on wild plants and agricultural crops. The market size for anti-Botrytis products was estimated at $15-25 billion USD (Elad et al. 2007). Now that we know that Botrytis caroliniana is abundant on Oxyria digyna leaves, we can conduct more specific research on the role of this fungus in plant health and plant communities in the alpine.
 
References:
 
Elad Y, Williamson B, Tudzynski P, Delen N (eds) (2007) Botrytis: Biology, Pathology and Control. Springer, Dordrecht, The Netherlands

Fernández-Ortuño D, Li XP, Wang F, Schnabel G (2012) First Report of Gray Mold of Strawberry Caused by Botrytis caroliniana in North Carolina. Plant Dis. doi: 10.1094/pdis-12-11-1018-pdn

Li X, Kerrigan J, Chai W, Schnabel G (2012) Botrytis caroliniana , a new species isolated from blackberry in South Carolina. Mycologia 103:650–658. doi: 10.3852/11-218
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Williamson B, Tudzynski B, Tudzynski P, Van Kan JAL (2007) Botrytis cinerea: The cause of grey mould disease. Mol Plant Pathol 8:561–580. doi: 10.1111/j.1364-3703.2007.00417.x