Huanglongbing (HLB), also known as citrus greening, is the most destructive disease of citrus worldwide. HLB is associated with the non-culturable bacterium, Candidatus Liberibacter asiaticus (CaLas) in the United States. The virulence mechanism of CaLas is largely unknown, partly because of the lack of a mutant library. In this study, Tobacco mosaic virus (TMV) and Nicotiana benthamiana (N. benthamiana) were used for large-scale screening of the virulence factors of CaLas. Agroinfiltration of 60 putative virulence factors in N. benthamiana led to the identification of four candidates that caused severe symptoms in N. benthamiana, such as growth inhibition and cell death. CLIBASIA_05150 and CLIBASIA_04065C (C-terminal of CLIBASIA_04065) could cause cell death in the infiltrated leaves at five days post infiltration. Two low-molecular-weight candidates, CLIBASIA_00470 and CLIBASIA_04025, could inhibit plant growth. By converting start codon to stop codon or frameshifting, the four genes lost their harmful effects to N. benthamiana. It indicated that the four virulence factors functioned at the protein level rather than at the RNA level. The subcellular localization of the four candidates was determined by confocal laser scanning microscope. CLIBASIA_05150 located in the Golgi apparatus; CLIBASIA_04065 located in the mitochondrion; CLIBASIA_00470 and CLIBASIA_04025 distributed in cells as free GFP. The host proteins interacting with the four virulence factors were identified by yeast two-hybrid. The host proteins interacting with CLIBASIA_00470 and CLIBASIA_04025 were overlapping. Based on the phenotypes, the subcellular localization and the host proteins identified by yeast two-hybrid, CLIBASIA_00470 and CLIBASIA_04025, functioned redundantly. The hypothesis of CaLas virulence was proposed. CaLas affects citrus development and suppresses citrus disease resistance, comprehensively, in a complicated manner. Ubiquitin-mediated protein degradation might play a vital role in CaLas virulence. Deep characterization of the interactions between the identified virulence factors and their prey will shed light on HLB. Eventually, it will help in developing HLB-resistant citrus and save the endangered citrus industry worldwide.

Rhizoctonia solani is one of the most important soil borne pathogenic fungi, causing disease in several important crops worldwide. The symptoms of R. solani infection are attributed to various plan...

Rhizoctonia solani is one of the most important soil borne pathogenic fungi, and causes disease of several important crops worldwide. The various symptoms of R. solani infection are damping off, root rot, stem cankers, crown rot and blights (Ogoshi 1996). For potato (Solanum tuberosum L.), R. solani has been associated with black scurf and stem canker causing both qualitative and quantitative damage (Djébali and Belhassen 2010). Isolates of R. solani anastomosis group 3 (AG3) are recognized as the predominant cause of these diseases on potato globally (Carling 1996) and in the northeast of China (Yang et al. 2017). In July 2017, two potato plants (cv. Favorita and Youjin-885) displaying visible brown, slightly sunken and sharped-edged lesions on subterranean stem and/or stolon typically associated with stem canker were collected from Harbin City (45°50'55''N, 126°50'27''E) and Kesan County (48°3'6''N, 125°51'46''E), located in the potato production regions of Heilongjiang Province, in China. Stem pieces (...

Intensive poultry farming produces substantial volumes of chicken manure that require effective and hygienic management. This study investigated a composite inoculant formulated with four microorganisms: Kocuria rosea ACCC 10488, Bacillus subtilis ACCC 60364, Trichoderma longibrachiatum ACCC 32584, and Lactobacillus plantarum ACCC 11118. This study investigated a composite inoculant formulated with four microorganisms obtained from the Agricultural Culture Collection of China (ACCC): Kocuria rosea ACCC 10488, Bacillus subtilis ACCC 60364, Trichoderma longibrachiatum ACCC 32584, and Lactobacillus plantarum ACCC 11118. Its performance was examined both without amendment and after addition of plant-derived bulking materials. The experiment included five treatments: untreated chicken manure (T1), the bulking-agent mixture without microbial addition (T2), a commercial inoculant combined with the same bulking materials (T3), the newly prepared inoculant without bulking agents (T4), and the newly prepared inoculant combined with the bulking mixture (T5). Three independent 50-kg piles were prepared for every treatment. Temperature was recorded for 45 days; physicochemical characteristics, odor indicators, nutrient concentrations, enzyme activities, seed-bioassay responses, and Ascaris egg mortality were evaluated over the initial 15 days. T5 reached 74 °C on days 5 and 10 and remained above 50 °C through day 30 at the plotted observation points. On day 15, this treatment had lower measured levels of odorous compounds, greater concentrations of available phosphorus and potassium, a 99% germination index, and complete mortality of the assayed Ascaris eggs. Collectively, T5 showed favorable changes across several indicators of early composting performance under the conditions tested. The study did not examine microbial community structure, persistence of the introduced strains, functional genes, whole-pile nutrient mass balances, or longer-term agronomic performance. Consequently, the data neither establish synergistic interactions among the component strains nor identify specific nutrient-transformation pathways.