The persimmon Diospyros kaki Thunb. is an important commercial and deciduous fruit tree. The fruits have proanthocyanidin (PA) content of >25% of the dry weight and are astringent. PAs cause astringency that is often undesirable for human consumption; thus, the removal of astringency is an important practice in the persimmon industry. Soluble PAs can be converted to insoluble PAs by enclosing the fruit in a polyethylene bag containing diluted ethanol. The genomic resource development of the persimmon is delayed because of its large and complex genome. Second-generation sequencing is an efficient technique for generating huge sequences that can represent a large number of genes and their expression levels.

The calcium-dependent protein kinases (CDPKs, also termed CPKs) are a large, diverse protein family that play significant roles in biotic and abiotic stress responses in plants. However, CDPKs in citrus are relatively unknown, as are their responses to drought stress (abiotic stress) and arbuscular mycorrhizal fungi (AMF) colonization. In this study, the citrus CDPKs were characterized by analyzing the presence of EF-hand and Pkinase domains and searching the citrus genome. Twenty-nine Citrus sinensis CDPKs (CsCDPKs) were identified on at least nine chromosomes in the citrus genome. Three clusters were found on chromosome 4 with three or two CsCDPKs, and 17 CsCDPKs showed syntenic relationships with Arabidopsis thaliana CPKs (AtCPKs). Twenty-nine CsCDPKs were expressed in the roots, and the regulation of the CsCDPKs was not always consistent with the cis-elements in their promoters. CsCDPK1, 2, 5, 6, 7, 8, 9, 13, 17, 18, 19, 21, 24, 25, 26, 27 and 29 were upregulated by AMF colonization, and CsCDPK3, 7 and 28 were downregulated. Drought-repressed expression of CsCDPK10, 11, 12, 15 and 16 induced CsCDPK20 and 22. Furthermore, AMF colonization and drought stress exerted synergistic effects; the expression levels of CsCDPK20 and CsCDPK22 were repressed in W_AMF treatment (well-watered with AMF) but induced in D_AMF treatment (drought stress with AMF). Together, these results provide a basis for further functional studies of the CsCDPK proteins and their responses to AMF and drought stress.

Histone acetyltransferase (HAT) and histone deacetylase (HDAC) family members control histone acetylation levels to regulate gene expression and play significant roles in microbe interactions and abioticstress responses. However, the HAT and HDAC family members in citrus have not yet been identified, and their responses to drought (abiotic stress) and arbuscular mycorrhizal fungi (AMF) colonization, remain unknown. In the present study, HAT and HDAC family genes were characterized in the citrus genome. A total of 14 CsHATs and 11 CsHDACs were identified in the citrus genome, of which 8 CsHATs and 7 CsHDACs showed syntenic relationships with Arabidopsis HATs and HDACs, respectively. Furthermore, the 14 CsHATs were classified into GNAT-MYST, TAFII250, MYST, CBP, and one citrus-unique family. The 11 CsHDACs were classified into SIR2, HD2, and RPD3/HDA1. Gene expression analysis showed AMF colonizationor drought induced the expression of CsHAT1, 2, 6, 7, 9, 11, 12, and 14, and repressed CsHDAC1, 2, 5, 6, 8, and 10. The regulation of HAT and HDAC expression was not always consistent with the cis-elements identified in their promoters. The present study offers useful insights into the citrus HAT and HDAC gene families and their expression in response to AMF colonization and drought stress.

Colletotrichum siamense infected the petiole and crown of strawberry (Fragaria × ananassa), and this anthracnose threatens strawberry production heavily in Hubei province. Characteristic the variation of transcript caused by C. siamense is important for anthracnose control of strawberry. In this study, RNA-seq analysis was used to monitor the strawberry transcripts in response of C. siamense at 0- and 6-days post-inoculation based on lesion measurement and hypha observation. The number of clean reads achieved for each sample was ranged from 5.68 to 8.12 Gb. The 0DPM vs 0DPI group had seven significantly differentially expressed transcripts, whereas the 6DPM vs 6DPI group exhibited 12,097 significantly differentially expressed transcripts. The differentially expressed transcripts of 6DPM vs 6DPI group were enriched in ‘metabolic process’ and ‘biological process’ in the biological process category and ‘oxidoreductase activity’ in the molecular function category by GO analysis. While ‘Starch and sucrose metabolism’, ‘Plant hormone signal transduction’ and ‘Phenylpropanoid biosynthesis’ pathways were significantly enriched by KEGG analysis. The expression of MYC2 in JA, the ETR in Eth and, the SnRK2 and ABF in ABA signal transduction pathways were promoted, whereas expression of the PR1 in SA, JZA1 in JA, and ERF in Eth signal transduction pathways were inhibited. In addition, the transcripts that encode enzymes involved in the ‘Phenylpropanoid biosynthesis’ pathway, such as PAL, CYP73A, CSE, 4CL, HTC, GSE and COMT were all inhibited showed by RNA-seq and qRT-PCR. This study provided basic information of strawberry responding to C. siamense infection.

Calmodulin-like (CML) proteins represent a diverse family of protein in plants, and play significant roles in biotic and abiotic stress responses. However, the involvement of citrus CMLs in plant responses to drought stress (abiotic stress) and arbuscular mycorrhizal fungi (AMF) colonization remain relatively unknown. We characterized the citrus CML genes by analyzing the EF-hand domains and a genome-wide search, and identified a total of 38 such genes, distributed across at least nine chromosomes. Six tandem duplication clusters were observed in the CsCMLs, and 12 CsCMLs exhibited syntenic relationships with Arabidopsis thaliana CMLs. Gene expression analysis showed that 29 CsCMLs were expressed in the roots, and exhibited differential expression patterns. The regulation of CsCMLs expression was not consistent with the cis-elements identified in their promoters. CsCML2, 3, and 5 were upregulated in response to drought stress, and AMF colonization repressed the expression of CsCML7, 9, 12, 13,20, 27, 28, and 35,and induced that of CsCML1, 2, 3, 5, 8, 10, 11, 14, 15, 16, 18, 25, 30, 33, and 37. Furthermore, AMF colonization and drought stress exerted a synergistic effect, evident from the enhanced repression of CsCML7, 9, 12, 13, 27, 28, and 35 and enhanced expression of CsCML2, 3, and 5 under AMF colonization and drought stress. The present study provides valuable insights into the CsCML gene family and its responses to AMF colonization and drought stress.

Crown rot (Colletotrichum siamense) of strawberry is a severe disease in Jingzhou, Hubei Province, China. Pathogen identification is the basis for disease prevention and resistance breeding. Nearly fifty isolates were achieved from 192 crown rot samples in this study. A number of 21 isolates were characterized as the pathogen of crown rot of strawberry by Koch’s postulates, and they were identified as Colletotrichum spp. by conidia morphology observation. The 21 isolates were divided into three groups based on colony morphology, and SCR-7, SCR-11 and SCR-16 belonged to each group were clustered into one group with C. siamense isolates by phylogenetic analysis of actin, β-Tubulin 2 and calmodulin sequences. In addition, the isolates of C. siamense SCR-7 showed the strongest pathogenicity of the three which caused highest values of lesion length and leaf temperature, and lowest leaf water content, photosynthetic rate, stomatal conductivity and even transpiration rate values. This study contributes to updating the Colletotrichum species associated with strawberry of China.