Leaf spot of Hosta ventricosa caused by Fusarium oxysporum in China

Leaf spot of Hosta ventricosa is a new disease in China. This disease seriously affects the ornamental value and greening function of H. ventricosa. Identification of the causal agent can prevent and control leaf spot in H. ventricosa and promote the healthy development of the H. ventricosa industry. Known incidents of leaf spot of H. ventricosa occurred in three places, and samples were collected. After the fungus were isolated, its pathogenicity was tested according to Koch’s postulates. Isolates ZE-1b and ZE-2b were identified as Fusarium oxysporum based on morphological features and multigene phylogenetic analyses of calmodulin (CMDA), RNA polymerase II subunit A (RPB1), RNA polymerase II second largest subunit (RPB2) and translation elongation factor 1-alpha (TEF1). These results provide a theoretical basis for the control of this disease of H. ventricosa.

Joint transcriptomic and metabolomic analysis reveals the mechanism of low-temperature tolerance in Hosta ventricosa

Hosta ventricosa is a robust ornamental perennial plant that can tolerate low temperatures, and which is widely used in urban landscaping design in Northeast China. However, the mechanism of cold-stress tolerance in this species is unclear. A combination of transcriptomic and metabolomic analysis was used to explore the mechanism of low-temperature tolerance in H. ventricosa. A total of 12 059 differentially expressed genes and 131 differentially expressed metabolites were obtained, which were mainly concentrated in the signal transduction and phenylpropanoid metabolic pathways. In the process of low-temperature signal transduction, possibly by transmitting Ca2+ inside and outside the cell through the ion channels on the three cell membranes of COLD, CNGCs and CRLK, H. ventricosa senses temperature changes and stimulates SCRM to combine with DREB through the MAPK signal pathway and Ca2+ signal sensors such as CBL, thus strengthening its low-temperature resistance. The pathways of phenylpropanoid and flavonoid metabolism represent the main mechanism of low-temperature tolerance in this species. The plant protects itself from low-temperature damage by increasing its content of genistein, scopolentin and scopolin. It is speculated that H. ventricosa can also adjust the content ratio of sinapyl alcohol and coniferyl alcohol and thereby alter the morphological structure of its cell walls and so increase its resistance to low temperatures.When subjected to low-temperature stress, H. ventricosa perceives temperature changes via COLD, CNGCs and CRLK, and protection from low-temperature damage is achieved by an increase in the levels of genistein, scopolentin and scopolin through the pathways of phenylpropanoid biosynthesis and flavonoid biosynthesis.

Joint Transcriptomic and Metabolomic Analysis Reveals the Mechanism of Low Temperature Tolerance in Hosta Ventricosa

Background: Hosta ventricosa is a robust ornamental perennial plant that can tolerate low temperatures, and which is widely used in urban landscaping design in Northeast China. However, the mechanism of cold stress tolerance in this species is unclear. Methods:This study used a combination of transcriptomic and metabolomic analysis to explore the mechanism of low temperature tolerance in H. ventricosa.Results: A total of 12 059 differentially expressed genes (DEGs) and 131 differentially expressed metabolites were obtained, which were mainly concentrated in the signal transduction and phenylpropanoid metabolic pathways. In the process of low temperature signal transduction, H. ventricosa is mainly through the ion channels on the three cell membranes of COLD, CNGCs and CRLK to transmit Ca2+ inside and outside the cell to sense temperature changes, and stimulate SCRM to combine with DREB through the MAPK signal pathway and Ca2+ signal sensors such as CBL. Strengthen the low temperature resistance of H. ventricosa. The pathways of phenylpropanoid and flavonoid metabolism represent the main mechanism of low temperature tolerance in this species. The plant protects itself from low temperature damage by increasing its content of genistein, scopolentin and scopolin. It is speculated that H. ventricosa can also adjust the content ratio of sinapyl alcohol and coniferyl alcohol and thereby alter the morphological structure of its cell walls and so increase its resistance to low temperatures.Conclusions: In H. ventricosa that is subjected to low temperature stress, temperature changes are perceived through COLD, CNGCs and CRLK, and protection from low temperature damage is achieved by an increase in the levels of genistein, scopolentin and scopolin through the pathways of phenylpropanoid biosynthesis and flavonoid biosynthesis.