ETHYLENE-INSENSITIVE TOBACCO LACKS NONHOST RESISTANCE AGAINST SOIL-BORNE FUNGI

Enhanced ethylene production is an early response of plants to pathoge n attack and has been associated with both resistance and susceptibili ty to disease. Tobacco plants were transformed with the mutant etr1-1 gene from Arabidopsis, conferring dominant ethylene insensitivity. Bes ides lacking known ethylene responses, these transformants (Tetr) did not slow growth when contacting neighboring plants, hardly expressed d efense-related basic pathogenesis-related proteins, and developed spon taneous stem browning. Whereas hypersensitive resistance to tobacco mo saic virus was unimpaired, Tetr plants had lost nonhost resistance aga inst normally nonpathogenic soil-borne fungi.