Characterization and Pathogenicity of Pestalotiopsis-Like Species Associated With Gray Blight Disease on Camellia sinensis in Anhui Province, China

Abstract

Gray blight disease, caused by Pestalotiopsis-like fungi, is one of the deadliest threats to tea (Camellia sinensis) production. However, little information is known about the traits and characteristics of this pathogen. Here, a systematic survey was performed, and a total of 20 representative isolates were obtained from the leaves of tea plants affected by gray blight in two main tea plantations located in Anhui Province, China. Further analyses showed that two isolates were identified as Neopestalotiopsis ellipsospora, three isolates were regarded as Pseudopestalotiopsis chinensis, one isolate was considered as Pseudopestalotiopsis camelliae-sinensis, and the remaining isolates belonged to Pseudopestalotiopsis spp., on the basis of morphological characteristics and multigene phylogenetic analyses of the internal transcribed spacer, β-tubulin, and translation elongation factor 1-α. Pathogenicity tests indicated that there were significant differences in virulence among the Neopestalotiopsis and Pseudopestalotiopsis isolates when inoculated on the leaves of the tea plant (C. sinensis ‘Shuchazao’). Furthermore, varied pathogenicity was also observed for the same isolate when inoculated on different varieties of tea plants. To our knowledge, this is the first record of Neopestalotiopsis ellipsospora and Pseudopestalotiopsis chinensis causing gray blight disease of tea plants in China.

Chemical Composition of a Supercritical Fluid (Sfe-CO2) Extract from Baeckea frutescens L. Leaves and Its Bioactivity Against Two Pathogenic Fungi Isolated from the Tea Plant (Camellia sinensis (L.) O. Kuntze)

“…In this study, β-caryophyllene and α-caryophyllene were the The hydrodistillation volatile oil of B. frutescens leaves grown in Vietnam was found to contain β-pinene (19.0%), γ-terpinene (11.7%), α-pinene (11.1%) and (E)-caryophyllene (7.1%) [1]. Similarly, the hydrodistillation volatile oil of B. frutescens leaves collected in Vietnam was shown to contain α-humulene (19.2%), β-caryophyllene (17.3%), baeckeol (13.8%), α-thujene (8.8%), linalool (5.6%) and eucalyptol (5.6%) [33]. From these results, it seems the essential oil composition of B. frutescens leaves exhibits high chemical variability [35].…”

“…Diseased tea leaves were collected from the tea plantation located in Cuona County, Shannan city, Tibet Autonomous Region in China. The pathogenic fungi were isolated from diseased leaves that presented visible grey blight disease and anthracnose symptoms using traditional method as previously described [12,33] and with slight modification. Briefly, the symptomatic leaves were surface-sterilized in 1% NaClO for 2 min, then in 70% ethanol for 1 min, rinsed three times in sterile water, and then margins of lesions were cut into small pieces and transferred into potato dextrose agar medium (PDA, Difco Company).…”

“…The major constituents of the volatile SFE-CO 2 extract were β-caryophyllene (28.05%), α-caryophyllene (24.02%), δ-cadinene (6.29%), eucalyptol (5.46%) and β-pinene (5.21%), followed by terpineol (4.54%), cubenol (2.81%) and γ-terpinene (2.49%). The volatile organic metabolites from B. frutescens have been investigated elsewhere and α-pinene, β-caryophyllene, γ-terpinene, terpineol, 1,8-cineole and linalool were the main components of B. frutescens volatile oils [1,33]. Furtnemore, Myrtaceae was divided into different chemotypes, according to the single most abundant compound, called dominant terpenes, in its plant volatile oils [33,34].…”

“…The volatile organic metabolites from B. frutescens have been investigated elsewhere and α-pinene, β-caryophyllene, γ-terpinene, terpineol, 1,8-cineole and linalool were the main components of B. frutescens volatile oils [1,33]. Furtnemore, Myrtaceae was divided into different chemotypes, according to the single most abundant compound, called dominant terpenes, in its plant volatile oils [33,34]. In most cases, 1,8-cineole or α-pinene are the most abundant and most common terpenes compounds in the majority of Myrtaceae foliar terpene profile, so in the vast majority of species (80%) there is an α-pinene or 1,8-cineole foliar terpene chemotype [34].…”

“…The B. frutescens volatile essential oil obtained by solid-phase micro extraction (SPME) presented γ-terpinene, o-cymene, α-pinene and Eucalyptol as major compounds. However, head-space extraction (HS) and conventional hydro distillation (HD) detected β-pinene, γ-terpinene, α-pinene and o-cymene as major compounds [33]. Meanwhile, the particle size of plant material is also an important factor in SFE and HD [28,36].…”