Disease Lesion Area Research Articles

Seasonal changes in the abundance Fusarium proliferatium, microbial endophytes and nutrient levels in the roots of hybrid bamboo Bambusa pervariabilis × Dendrocalamopsis grandis.

Plant root pathogens invade the soil around plant roots, disturbing the systemic balance, reducing plant defenses, and causing severe disease. At present, there are few studies on the severity of plant diseases caused by pathogen invasion in different seasons and how pathogens affect root microecology. In this study, we compared the levels of nutrients in the root tissues of the two groups of plants. We used 16S and ITS amplicon sequencing with Illumina NovaSeq 6000 to compare seasonal changes in the composition and structure of microbial communities from healthy roots of bamboo Bambusa pervariabilis × Dendrocalamopsis grandis and roots infected by the soilborne pathogen Fusarium proliferatum. We have found that the invasion of the pathogen led to a substantial decrease in nutrient elements in bamboo roots, except for nitrogen. The pathogen presence correlated with seasonal changes in the bamboo root microbiome and decreased bacterial richness in diseased plants. The root microbial community structure of healthy plants was more stable than that of their diseased counterparts. Furthermore, we identified the lesion area and relative abundance of F. proliferatum were significant predictors of disease progression. The potassium tissue content and the disease lesion area were identified as factors linked with the observed changes in the bamboo root microbiome. This study provides a theoretical foundation for understanding the seasonal dynamics F. proliferatum, an economically important soilborne pathogen of hybrid bamboo grown in Sichuan Province, China.

Quantifying impacts of stony coral tissue loss disease on corals in Southeast Florida through surveys and 3D photogrammetry.

Since 2014, stony coral tissue loss disease (SCTLD) has contributed to substantial declines of reef-building corals in Florida. The emergence of this disease, which impacts over 20 scleractinian coral species, has generated a need for widespread reef monitoring and the implementation of novel survey and disease mitigation strategies. This study paired SCTLD prevalence assessments with colony-level monitoring to help improve understanding of disease dynamics on both individual coral colonies and at reef-wide scales. Benthic surveys were conducted throughout the northern Florida Reef Tract to monitor the presence/absence of disease, disease prevalence, and coral species affected by SCTLD. Observed SCTLD prevalence was lower in Jupiter and Palm Beach than in Lauderdale-by-the-Sea or St. Lucie Reef, but there were no significant changes in prevalence over time. To assess colony-level impacts of the disease, we optimized a low-cost, rapid 3D photogrammetry technique to fate-track infected Montastraea cavernosa coral colonies over four time points spanning nearly four months. Total colony area and healthy tissue area on fate-tracked colonies decreased significantly over time. However disease lesion area did not decrease over time and was not correlated with total colony area. Taken together these results suggest that targeted intervention efforts on larger colonies may maximize preservation of coral cover. Traditional coral surveys combined with 3D photogrammetry can provide greater insights into the spatiotemporal dynamics and impacts of coral diseases on individual colonies and coral communities than surveys or visual estimates of disease progression alone.

Does genetic diversity of grass improve yield, digestibility, and resistance to weeds, pests and disease infection?

ABSTRACTIntraspecies genetic level diversity has the potential to improve ecosystem functions and services, similar to that by species-level diversity. Although yield, pollination, and pest and disease control have been enhanced by crop genetic diversity, mixing multiple cultivars of grass within a species in an agricultural field have not been fully tested by farmers.We, therefore, tested whether multiple ecosystem functions are increased in a grass mixture of multiple cultivars compared to monoculture and whether this relationship differs with soil fertility. We performed monocultures of four Orchard Grass cultivars and a mixture of these cultivars with and without fertilizer application and examined the aboveground net primary productivity (ANPP), their stability, dry matter digestibility, and resistance to weed, pest, and disease. We found significant differences between cultivars in the second yield and disease lesion area on the leaf, but not between mixed culture and monoculture. Moreover, no significant difference was found in the first and third yields in terms of stability, dry matter digestibility, and leaf damage by insects, although the number of leaves damaged by insects for mixed culture was less than half of that on average for monoculture. Although genetic diversity is not always an important driver of ecological processes due to fluctuation among plots, it may play a role in pest control of agricultural land in the long term.