'TAL proteins key tool on bacterial blight of rice'

Underscoring the role of TAL (Transcription Activator Like) effectors in providing information on how bacterial blight (BB) works in rice, Jan Leach of Colorado State University, US, said they were becoming very important bio-technology tools.

TALs are xanthamonous proteins that are injected into the host cells (rice plants). These then localise themselves into nucleus of plant cells and activate the transcription of susceptible and resistant genes. The genes they activate sometimes are called as Os Sweet genes 11 and 14, which encode sugar transporters in BB susceptible plants.

However, she said functions of many TAL effectors were still not known. "We have a long way to go in the race-specific resistance by way of TALs. The rice targets for many TAL effectors are predicted and have not been proved yet," said Leach while speaking at the fourth international conference on Bacterial Blight here recently.

The event was jointly organised by CSIR-Centre for Cellular and Molecular Biology (CCMB), Directorate of Rice Research (DRR) and Society for Advancement of Rice Research.

BB is caused by bacterial pathogen, Xanthomonas oryzae pv. oryzae (Xoo), which cannot be treated chemically and can risk 50 per cent crop. The best way to deal is to develop host plant (resistant) varities.

"We need funding for research. The virulence function and bio-targeting is still far away," she added. At present, there are more than 40 gene varieties and 11 pathotypes detected for various races of rice.

CSIR-CCMB, in collaboration with the DRR, has jointly developed the improved bacterial-resistant 'samba masuri' variety.