A R2R3-MYB Transcription Factor, VvMYBC2L2, Functions as a Transcriptional Repressor of Anthocyanin Biosynthesis in Grapevine (Vitis vinifera L.)

In grapevine, the MYB transcription factors play an important role in the flavonoid pathway. Here, a R2R3-MYB transcription factor, VvMYBC2L2, isolated from Vitis vinifera cultivar Yatomi Rose, may be involved in anthocyanin biosynthesis as a transcriptional repressor. VvMYBC2L2 was shown to be a nuclear protein. The gene was shown to be strongly expressed in root, flower and seed tissue, but weakly expressed during the fruit development in grapevine. Overexpressing the VvMYBC2L2 gene in tobacco resulted in a very marked decrease in petal anthocyanin concentration. Expression analysis of flavonoid biosynthesis structural genes revealed that chalcone synthase (CHS), dihydroflavonol 4-reductase (DFR), leucoanthocyanidin reductase (LAR) and UDP glucose flavonoid 3-O-glucosyl transferase (UFGT) were strongly down-regulated in the VvMYBC2L2-overexpressed tobacco. In addition, transcription of the regulatory genes AN1a and AN1b was completely suppressed in transgenic plants. These results suggested that VvMYBC2L2 plays a role as a negative regulator of anthocyanin biosynthesis.

Isolation and characterization of antagonistic bacteria with the potential for biocontrol of soil-borne wheat diseases

AIM

The aim of this study was to identify efficient plant-beneficial rhizobacterium that has the potential to be developed as biocontrol agent for the control of wheat soil-borne diseases.

METHODS AND RESULTS

Rhizosphere soil samples were collected from a wheat field located in Taian City. Numerous bacteria were isolated and screened for antagonistic activity against soil-borne plant pathogenic fungi by performing dual-culture assays. Among them, XH-9 was selected for its highly antagonistic activity and others growth-promoting characteristics. Subsequently, the strain was identified as Bacillus amyloliquefaciens subsp. plantarum based on phylogenetic analysis of 16S rDNA sequence. Pot experiment indicated that XH-9 has good capacities for wheat, corn, and chili root colonization and considerably increased the biometric parameters of wheat seedlings. Quantitative real-time polymerase chain reaction experiments showed that the amount of Fusarium oxysporum associated with the XH-9 after treatment significantly decreased compared with control group.

CONCLUSIONS

Bacillus amyloliquefaciens subsp. plantarum XH-9 has the potential as biocontrol agent when applied in local arable land to prevent damage caused by F. oxysporum and other phytopathogens.

SIGNIFICANCE AND IMPACT OF THE STUDY

The development of biocontrol strategies for reducing the damage caused by plant pathogens is fully in accord with the current principles of sustainability.