[Molecular identification of geminivirus inducing vein yellowing in Abelmoschus manihot].

OBJECTIVE: The virus isolate H was identified by molecular biology,it was collected from Abelmoschus manihot plant showing leaf curl,yellow vein symptoms in Guangxi Botanical Garden of Medicinal Plant. METHODS: The virus isolate H was observed in electron micrograph, and conformed detected by PCR using universal primer pair for the genus Geminivirus. RESULTS: The results indicated that all sequences homologous to the specific fragment belonged to the genus Begomovirus of the family Geminiviridae. There was the highest similarity shared 95% homology at nucleotide between the specific fragment and DNA-A of Emilia yellow vein virus isolates. CONCLUSION: These findings suggested that there was geminiviridea in Abelmoschus manihot, and the disease probably caused by Emilia yellow vein virus.

[Antagonism of Trichoderma spp. to fungi caused root rot of Sophora tonkinensis].

OBJECTIVE: To study the antagonism of Trichoderma spp. to fungi S9(Fusarium solani)which caused root rot of Sophora tonkinensis and discuss the further develop prospects of microbial biological control in soil-borne diseases on Chinese herbal medicines. METHODS: Antagonism of H2 (Trichoderma harsianum), M6 (Trichoderma viride) and K1 (Trichoderma koningii) to Fusarium solani were researched by growth rate and confront culture. And their mechanisms were discussed. RESULTS: H2 and M6 had obvious competitive advantage, the growth rate of which were 1.43-2.72 times and 1.43-1.95 times as S9 respectively. The space competitive advantage of K1 was relatively weak; the growth rate was slower than S9. The antagonism of three species of Trichoderma spp. to S9 was in varying degrees. The antagonism to S9 of M6 and H2 was better,the inhibition rate were 100% and 82.35% respectively, even cultivated S9 for three days in advance. And their inhibition indexes were both reached class I. The inhibition index and inhibition rate of K1 was respectively 46.36% and class IV. The Trichoderma spp. could cause S9 mycelium to appear some phenomenon just like fracture, constriction reduced, digestion, etc. which were observed under the microscope. CONCLUSION: Trichoderma harsianum and Trichoderma viride showed the further develop prospects in the fight against soil-borne disease on Chinese herbal medicines.

[Identification of pathogens causing root rot of Sophora tonkinensis].

OBJECTIVE: To identify the pathogens what caused of root rot, it can provide method of theoretical gist of integrated pest management of these kinds of diseases in the future. METHODS: Pathogens from rotten root of Sophora tonkinensis were isolated by tissue isolation. Their morphological characteristics were observed and rDNA-ITS sequence were sequenced, then analyzed by Blast in GenBank. RESULTS: Round colony in PDA medium. The aerial mycelium was thin, white, light gray and yellowish brown eustroma was on the surface of material. The surface of base material was flesh. Large number of small conidia ware oval, kidney-shaped, 8-16 microm x 2.5 -4 microm. And the large conidia just like Matt spore type, which had 3 to 5 septums. The length of rDNA-ITS of the fungi was 553 bp, which the ITS region sequences compared with the sequence of Fusarium solani (accession number: AB518683.1, AB470903.1, AB369488.1, AJ608989.1, GQ365154.1, EF152426.1), and Fusarium oxysporum (accession number: GQ922558.1, GQ922559.1, DQ452447.1) homology reached 99%. CONCLUSION: Combination of two identification methods,it arrived at the cause of root rot pathogen fungi was Fusarium solani.