Abstract
Diaporthe species are associated with Citrus as endophytes, pathogens, and saprobes worldwide. However, little is known about Diaporthe as endophytes in Citrus grandis in China. In this study, 24 endophytic Diaporthe isolates were obtained from cultivated C. grandis cv. “Tomentosa” in Huazhou, Guangdong Province in 2019. The nuclear ribosomal internal transcribed spacer (ITS), partial sequences of translation elongation factor 1-α (tef1), β-tubulin (tub2), and partial calmodulin (cal) gene regions were sequenced and employed to construct phylogenetic trees. Based on morphology and combined multigene phylogeny, eleven Diaporthe species were identified including two new species, Diaporthe endocitricola and D. guangdongensis. These are the first report of D. apiculata, D. aquatica, D. arecae, D. biconispora, D. limonicola, D. masirevicii, D. passifloricola, D. perseae, and D. sennae on C. grandis. This study provides the first intensive study of endophytic Diaporthe species on C. grandis cv. tomentosa in China. These results will improve the current knowledge of Diaporthe species associated with C. grandis. The results obtained in this study will also help to understand the potential pathogens and biocontrol agents and to develop a platform in disease management.
Highlights
Diaporthe Nitschke (1870) belongs to Diaporthaceae (Senanayake et al, 2017) which comprises plant pathogens, endophytes, and saprobes (Udayanga et al, 2011; Huang et al, 2013, 2015)
Note: In the phylogenetic tree developed using internal transcribed spacer (ITS), tef1, tub2, and cal, three isolates obtained in this study developed a sister clade to D. melonis (CBS 507.78) with 100% maximum likelihood, 100% maximum parsimony bootstrap, and 1.0 Bayesian posterior probability values
Note: In the combined multigene phylogenetic analysis of ITS, tef1, tub2, and cal, eight strains isolated in this study developed a well-supported clade with the D. passifloricola (CPC 27480) with 96% maximum likelihood (ML), 96% maximum parsimony (MP) bootstrap and 1.0 BYPP values
Summary
Diaporthe Nitschke (1870) belongs to Diaporthaceae (Senanayake et al, 2017) which comprises plant pathogens, endophytes, and saprobes (Udayanga et al, 2011; Huang et al, 2013, 2015). The classification of Diaporthe depended mainly on morphology, culture characteristics, and host affiliations (Udayanga et al, 2011). ITS, tef, tub, cal, and partial histone (HIS) genes have been used for species delimitation in this genus (Udayanga et al, 2014a; Santos et al, 2017; Guarnaccia and Crous, 2018; Manawasinghe et al, 2019). Endophytic Diaporthe on Citrus grandis a worldwide distribution and diverse host associations (Udayanga et al, 2014b). More than one Diaporthe species have been reported on a single host (Guarnaccia and Crous, 2018; Manawasinghe et al, 2019) and one species can be associated with more than one host in the same country or region (Santos and Phillips, 2009; Diogo et al, 2010; Guarnaccia et al, 2018b; Manawasinghe et al, 2019)
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