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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 8/5/2010 Publication Date: 12/2/2011 Citation: Jia, Y. 2011. Plants and pathogens engage in trench warfare-knowledge learned from natural variation of rice blast resistance gene Pi-ta and the corresponding avirulence gene AVR-Pita1 [abstract]. In: Fifth International Rice Blast Conference, August 12-14, 2010, Little Rock, Arkansas. p. 9. Interpretive Summary: Technical Abstract: Plants and pathogens have existed together and coevolved for millions of years. As a result of this relationship, sophisticated multifaceted recognition and resistance mechanisms have evolved in plants in order to prevent or reduce infection by pathogens. This selection process may drive the evolution of pathogen genes to counteract plant defenses and promote more disease. Rice blast disease is one of the most destructive plant diseases that threatens stable rice production in the U.S. and worldwide. For several decades, the Pi-ta gene in rice has been deployed which confers resistance to races of the blast fungus containing the corresponding avirulence gene AVR-Pita1. How Pi-ta has evolved to cope with AVR-Pita1 has been the subject of our investigation at USDA-ARS Dale Bumpers National Rice Research Center. Pi-ta is located near the centromere of a rice chromosome, a region that is relatively stable. Pi-ta encodes a predicted cytoplasmic protein with nucleotide binding sites and leucine rich repeats (NBS-LRR) that resembles most cloned plant resistance gene products. Our survey of rice germplasm revealed that there is only one resistant Pi-ta allele, however, it produces 12 proteins each of them capable of preventing infection of up to 10 races of the blast fungus. Moreover, the fungus is known to have its own Houdini-like talents to attack the host plant. Not only is the AVR-Pita1 gene is located near the telomere, an unstable region of blast fungus, but also the AVR-Pita1 protein has been shown to be frequently altered in field blast populations. Taken together, these findings suggest that Pi-ta engages in trench warfare with AVR-Pita1 with both organisms maintaining an array of strategies to cause/prevent disease. Trench warfare hypothesis of Pi-ta/AVR-Pita1 needs to be further tested. However, it could have a significant impact on crop protection since gene-for-gene interactions have been observed in plant responses to numerous destructive bacterial, viral, fungal pathogens and insects. |
