摘要：
Carbamoyl phosphate synthetase is involved in arginine biosynthesis in many organisms. In this study, we investigate the biological function of Cpa1, a small subunit of carbamoyl phosphate synthetase of Colletotrichum gloeosporioides. The deletion of the CPA1 gene affected vegetative growth, arginine biosynthesis, and fungal pathogenicity. Genetic complementation with native CPA1 fully recovered all these defective phenotypes. We observed that Cpa1-RFP fusion protein is localized at the mitochondria, which is consistent with Cpa2, a large subunit of carbamoyl phosphate synthetase. We identified the proteins that interact with Cpa1 by using the two-hybrid screen approach, and we showed that Dut1 interacts with Cpa1 but without Cpa2 in vivo. Dut1 is dispensable for hyphal growth, appressorial formation, and fungal pathogenicity. Interestingly, the Dut1-Cpa1 complex is localized at the mitochondria. Further studies showed that Dut1 regulates Cpa1-Cpa2 interaction in response to arginine. In summary, our studies provide new insights into how Cpa1 interacts with its partner proteins to mediate arginine synthesis. (C) 2020 British Mycological Society. Published by Elsevier Ltd. All rights reserved.
作者机构：
[洪艳云; 易图永; 张玮] College of Plant Protection, Hunan Agricultural University / Hunan Provincial Key Laboratory for Biology and Control of Plant Pests, Changsha, 410128, China;[刘登望; 李林; 张博文] Institute of Dryland Crops of Hunan Agricultural University, Changsha, 410128, China
通讯机构：
[Yi, T.-Y.] C;[Li, L.] I;College of Plant Protection, China;Institute of Dryland Crops of Hunan Agricultural UniversityChina
关键词：
Asian citrus psyllid (ACP);imidacloprid;resistance;symbiotic fungus;thiamethoxam
摘要：
The Asian citrus psyllid (ACP), Diaphorina citri (Kuwayama) (Hemiptera: Liviidae), is a notorious Rutaceae plant pest. Frequent and extensive use of pesticides has resulted in severe insecticide resistance in ACP populations. Fully understanding the mechanism of ACP resistance to pesticides is vital for us to control or delay the development of resistance. Therefore, we compared the difference in resistance to imidacloprid and thiamethoxam between Hunan (Yongzhou, Chenzhou) and Guangdong (Guangzhou) ACP populations and analyzed the correlations between the resistance level and genes and symbiotic fungi. The results showed that the resistance of the Guangdong ACP population to imidacloprid and thiamethoxam was lower than that of Hunan ACP population, and the relative expression of genes associated with P450 mono-oxygenase and acetylcholinesterase was significantly lower in the Guangdong ACP population than in Hunan ACP population. The differences of mean relative abundances of four symbiotic bacteria among three populations were marginally significant; however, the mean relative abundance of 16 fungi among three populations was significantly different, and positive linear correlations were observed between the resistance level and two fungi (Aspergillus niger and Aureobasidium pullulans) and two genes (CYP4C70 and CYP4DB1). Negative correlations were only observed between the resistance level and two fungi (Golubevia pallescens and Acremonium sclerotigenum). Moreover, four fungi were unique to the Chenzhou population which was the highest resistance to imidacloprid and thiamethoxam. These findings suggested the P450 mono-oxygenase and symbiotic fungi together affected ACP resistance to imidacloprid and thiamethoxam. In the future, we may use environmental G. pallescens and A. sclerotigenum to control or delay ACP resistance.
摘要：
Citrus Huanglongbing (HLB) is one of the most devastating citrus diseases worldwide. Sensitive and accurate assays are vital for efficient prevention of the spread of HLB-associated "Candidatus Liberibacter spp". "Candidatus Liberibacter spp" that infect Citrus includes "Candidatus Liberibacter asiaticus" (Las), "Candidatus Liberibacter africanus" (Laf) and "Candidatus Liberibacter americanus" (Lam). Of them, Las is the most widespread species. In this study, a set of nested PCR primer pairs were screened to diagnose Las, and the nested PCR method greatly enhanced the sensitivity to detect Las up to 10 times and 100 times compared to qPCR and conventional PCR, respectively. Totally, 1112 samples from 5 different citrus cultivars in 39 different counties and cities were assayed by nested PCR. The results show that 384 samples were HLB-infected; the highest positive detection rate was 79.7% from the lopsided fruit samples, and the lowest positive detection rate was 16.3% from the apical dieback samples. The results indicate that the designed nested PCR primer pairs can detect Las from different symptomatic tissues, different citrus cultivars and different geographic regions. The set of nested PCR primers designed in the present study will provide a very useful supplementation to the current approaches for Las detection.
摘要：
Shennongjia Rhinopithecus roxellana (SNJ R. roxellana) is the smallest geographical population of R. roxellana. The phylogenetic relationships among its genera and species and the biogeographic processes leading to their current distribution are largely unclear. To address these issues, we resequenced and obtained a new, complete mitochondrial genome of SNJ R. roxellana by next-generation sequencing and standard Sanger sequencing. We analyzed the gene composition, constructed a phylogenetic tree, inferred the divergence ages based on complete mitochondrial genome sequences, and analyzed the genetic divergence of 13 functional mtDNA genes. The phylogenetic tree and divergence ages showed that R. avunculus (the Tonkin snub-nosed monkey) was the first to diverge from the Rhinopithecus genus ca. 2.47 million years ago (Ma). Rhinopithecus bieti and Rhinopithecus strykeri formed sister groups, and the second divergence from the Rhinopithecus genus occurred ca. 1.90 Ma. R. roxellana and R. brelichi diverged from the Rhinopithecus genus third, ca. 1.57 Ma. SNJ R. roxellana was the last to diverge within R. roxellana species in 0.08 Ma, and the most recent common ancestor of R. roxellana is 0.10 Ma. The analyses on gene composition showed SNJ R. roxellana was the newest geographic population of R. roxellana. The work will help to develop a more accurate protection policy for SNJ R. roxellana and facilitate further research on selection and adaptation of R. roxellana.
