Managing the ecology of foliar pathogens: ecological tolerance in crops

Abstract

The phyllosphere is a rich and varied microbial community comprising organisms with diverse functional types. Its composition is strongly influenced by both genotypic and environmental factors, many of which can be manipulated by breeding, agronomy and crop protection strategies in an agricultural context. These factors also affect the complex interactions between the microbes, which in turn affect their interaction with their host plant. Whether or not an organism becomes pathogenic and the subsequent expression of disease are also influenced by all these factors. Understanding the population dynamic balance between the organisms of the phyllosphere as an ecological system should lead to new approaches in agronomy, crop protection and breeding that enhance sustainability, where the previously presumed requirement to eliminate putative pathogens is replaced by management that favours dominance of beneficial organisms and contains putative pathogens in asymptomatic or stable states.

Sowing date reduces the incidence of wheat blast disease

“…High losses (group A), were observed for the genotypes with a low DI (EP066055, EP063044, and EP064026 lines) but also for the EP066066 and EP063065 lines, which showed the highest and an intermediate DI of 0.685 and of 0.524, respectively. Plants that are disease tolerant produce good yields even when infected by pathogens (Barrett et al, 2009;Newton et al, 2010); therefore, it was inferred that the EP066055, EP063044, and EP064026 lines had little tolerance to blast disease. The group of genotypes with the lowest DI (group c), had yield losses less than 70%.…”

Enigmatic Sebacinales

“…However, the possibility exists that bacterium-originated N-acyl homoserine lactones are involved in stimulating plant responses (Schikora et al 2011). Rhizobium radiobacter is considered to be identical with Agrobacterium tumefaciens, a soil-borne pathogen (Newton et al 2010b) that can lack virulence genes. It can be expected that future studies reveal an interphylum network of nutritional interactions, as recently shown for AMF fungi (Ghignone et al 2012).…”

Endophytic Microbiota Associated with the Root Tips and Leaves of Baccharis dracunculifolia

“…These data were supported by Shannon and the Simpson indexes (Table 1). Both Chao1 and ACE estimators indicated higher taxonomic richness in the roots compared to the leaves, which may be due to the fact that the surface and the interior of the leaves have water and resource limitations, high UV exposure and wide temperature shifts [ 16,32 ]. In contrast, the rhizosphere harbors a high density of soil bacteria that compete for plantderived nutrients [ 33 ].…”