RESUMO

Plant-endophytic microbes affect plant growth, development, nutrition, and resistance to pathogens. However, how endophytic microbial communities change in different strawberry plant compartments after Fusarium pathogen infection has remained elusive. In this study, 16S and internal transcribed spacer rRNA amplicon sequencing were used to systematically investigate changes in the bacterial and fungal diversity and composition in the endophytic compartments (roots, stems, and leaves) of healthy strawberries and strawberries with Fusarium wilt, respectively. The analysis of the diversity, structure, and composition of the bacterial and fungal communities revealed a strong effect of pathogen invasion on the endophytic communities. The bacterial and fungal community diversity was lower in the Fusarium-infected endophytic compartments than in the healthy samples. The relative abundance of certain bacterial and fungal genera also changed after Fusarium wilt infection. The relative abundance of the beneficial bacterial genera Bacillus, Bradyrhizobium, Methylophilus, Sphingobium, Lactobacillus, and Streptomyces, as well as fungal genera Acremonium, Penicillium, Talaromyces, and Trichoderma, were higher in the healthy samples than in the Fusarium wilt samples. The relative abundance of Fusarium in the infected samples was significantly higher than that in the healthy samples, consistent with the field observations and culture isolation results for strawberry wilt. Our findings provide a theoretical basis for the isolation, identification, and control of strawberry wilt disease.

RESUMO

WRKY genes and jasmonic acid (JA) play a crucial role in plants' responses against biotic and abiotic stress. However, the regulating mechanism of WRKY genes on strawberry fruits' resistance against Botrytis cinerea is largely unknown, and few studies have been performed on their effect on the JA-mediated defense mechanism against B. cinerea. This study explored the effect of FaWRKY25 on the JA-mediated strawberry resistance against B. cinerea. Results showed that the JA content decreased significantly as the fruits matured, whereas the FaWRKY25 expression rose substantially, which led to heightened susceptibility to B. cinerea and in strawberries. External JA treatment significantly increased the JA content in strawberries and reduced the FaWRKY25 expression, thereby enhancing the fruits' resistance against B. cinerea. FaWRKY25 overexpression significantly lowered the fruits' resistance against B. cinerea, whereas FaWRKY25 silencing significantly increased resistance. Moreover, FaWRKY25 overexpression significantly lowered the JA content, whereas FaWRKY25 silencing significantly increased it. FaWRKY25 expression level substantially affects the expression levels of genes related to JA biosynthesis and metabolism, other members of the WRKY family, and defense genes. Accordingly, FaWRKY25 plays a crucial role in regulating strawberries' resistance against B. cinerea and may negatively regulate their JA-mediated resistance mechanism against B. cinerea.

Assuntos

Botrytis/patogenicidade , Ciclopentanos/farmacologia , Fragaria/genética , Interações Hospedeiro-Patógeno/genética , Oxilipinas/farmacologia , Reguladores de Crescimento de Plantas/farmacologia , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Sequência de Aminoácidos , Botrytis/crescimento & desenvolvimento , Ciclopentanos/metabolismo , Resistência à Doença/genética , Fragaria/classificação , Fragaria/imunologia , Fragaria/microbiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Patógeno/imunologia , Oxilipinas/metabolismo , Filogenia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Reguladores de Crescimento de Plantas/metabolismo , Imunidade Vegetal/genética , Proteínas de Plantas/antagonistas & inibidores , Proteínas de Plantas/imunologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/imunologia

RESUMO

Ornamental purslanes (Portulaca L.) are a popular annual bedding and container plant for landscaping. Little information is available concerning the genetic characterization of ornamental purslane resources thus far. The purpose of this study was to investigate the genetic diversity and relationships present in a collection of ornamental purslanes from Portulaca umbraticola and P. grandiflora cultivated in China, using sequence-related amplified polymorphism (SRAP) markers. The genotyping showed that 16 SRAP primer combinations totally produced 261 informative fragments and averaged 16.31 per primer combination. The major allele frequency and Nei's gene diversity was calculated at 0.78 and 0.31 across the loci, indicative of a moderate low diversity. Both unweighted pair group method with arithmetic average (UPGMA) clustering and a Bayesian-based approach apparently assigned the whole accessions into two sub-groups: P. umbraticola and P. grandiflora, well concordant with the botanical classification and flower type. The findings provide a brandnew understanding of genetic diversity and population structure present in ornamental purslane, and benefit a sound design of breeding programs in future.