Diaporthe sapindicola sp. nov. Causes Leaf Spots of Sapindus mukorossi in China

Sapindus mukorossi Gaertn. (Sapindaceae), soapberry is an important biodiesel tree in southern China. In recent years, leaf spot disease on soapberry has been observed frequently in soapberry germplasm repository, Jianning County, Sanming City, Fujian Province, China. The symptoms initially appeared as irregular small yellow spots, and the center of the lesions became dark brown with time. Three fungal isolates from lesions were collected. Koch's postulates were performed, and their pathogenicity was confirmed. Morphologically, α conidia from diseased tissues were 1-celled, hyaline, smooth, clavate or ellipsoidal, biguttulate, and measured 6.2–7.2 × 2.3–2.7 μm. In addition, the three isolates in this study developed three types (α, β, and γ) of conidia on PDA, and their morphological characteristics matched those of Diaporthe. A phylogenetic analysis based on ITS, TEF, TUB, HIS, and CAL sequence data determined that the three isolates are a new species of Diaporthe. Based on both morphological and phylogenetic analyses, the causal fungus, Diaporthe sapindicola sp. nov. was described and illustrated.

Identification of the gut commensal Candida parapsilosis as a causative fungus for the development of high fat-diet induced obesity in mice

Gut fungi is known to play many important roles in human health regulations. Herein, we investigated the anti-obesity efficacy of the antifungal antibiotics (amphotericin B, fluconazole and 5-fluorocytosine) in the high fat diet-fed (HFD) mice. Supplementation of amphotericin B or fluconazole in water effectively inhibited obesity and its related disorders, whereas 5-fluorocytosine exhibited little effects. The gut fungus Candida parapsilosis was identified as a key commensal fungus related to the diet-induced obesity by the culture-dependent method and the inoculation assay with C. parapsilosis in the fungi-free mice. In addition, the increase of free fatty acids in the gut due to the production of fungal lipases from C. parapsilosis was confirmed as one mechanism by which C. parapsilosis promotes obesity. The current study demonstrates the gut C. parapsilosis as a causal fungus for the development of diet-induced obesity in mice and highlights the therapeutic strategy targeting the gut fungi.

Coniothyrium glycines (red leaf blotch).

Red leaf blotch affects soyabean in central and southern Africa. The disease and the causal fungus (Coniothyrium glycines) were first reported in Ethiopia in 1957. C. glycines is native to Africa, living on the native legume, Neonotonia wightii, and perhaps other native or non-native legumes. The jump of the pathogen to soyabean occurred as early as 1957 and reports of the occurrence of red leaf blotch have increased along with soyabean production in Africa. The disease is currently a serious threat to soyabean production in sub-Saharan African countries with losses of up to 70% reported. C. glycines is considered a threat to soyabean-producing countries such as Brazil and the USA. The pathogen is not known to be disseminated by seed or wind. Infection is thought to occur via rainsplash of soilborne inoculum onto the leaves of soyabean plants. Symptoms include characteristic dark red spots on the upper leaf surface and reddish-brown lesions with dark borders on the lower surface. Premature leaf drop may occur in heavy disease conditions, releasing sclerotia back into the soil. The disease is favoured by wet, humid conditions.

Coniothyrium glycines (red leaf blotch).

Red leaf blotch affects soyabean in central and southern Africa. The disease and the causal fungus (Coniothyrium glycines) were first reported in Ethiopia in 1957. C. glycines is native to Africa, living on the native legume, Neonotonia wightii, and perhaps other native or non-native legumes. The jump of the pathogen to soyabean occurred as early as 1957 and reports of the occurrence of red leaf blotch have increased along with soyabean production in Africa. The disease is currently a serious threat to soyabean production in sub-Saharan African countries with losses of up to 70% reported. C. glycines is considered a threat to soyabean-producing countries such as Brazil and the USA. The pathogen is not known to be disseminated by seed or wind. Infection is thought to occur via rainsplash of soilborne inoculum onto the leaves of soyabean plants. Symptoms include characteristic dark red spots on the upper leaf surface and reddish-brown lesions with dark borders on the lower surface. Premature leaf drop may occur in heavy disease conditions, releasing sclerotia back into the soil. The disease is favoured by wet, humid conditions.

Insights into the susceptibility of rice to a floral disease

Crop floral diseases are economically important as they reduce grain yield and quality and even introduce food toxins. Rice false smut has emerged as a serious floral disease producing mycotoxins. However, very little is known on the interaction mechanisms between rice flower and the causal fungus Ustilaginoidea virens. Here we show that a conserved anti-fungal immunity in rice flower is disarmed by U. virens via a secreted protein UvChi1. UvChi1 functioned as an essential virulence factor and directly interacted with the chitin receptor CEBiP and co-receptor CERK1 in rice to disrupt their oligomerizations and subsequent immune responses. Moreover, intraspecific-conserved UvChi1 could target OsCEBiP/OsCERK1 receptor complex in at least 98.5% of 5232 surveyed rice accessions. These results demonstrate that U. virens utilizes a crucial virulence factor to subvert chitin-triggered flower immunity in most rice varieties, providing new insights into the susceptibility of rice to false smut disease.