تأثير سن گياه لوبيا بر بيان phlA ، ژن بيوسنتز آنتي‌بيوتيك 2و4- دي استيل فلورو گلوسينول در Pseudomonas fluorescens استرين CHA0 در شرايط نوتوبيوتيك

INFLUENCE OF BEAN PLANT AGE ON THE EXPRESSION OF 2, 4- DIACETYLPHLOROGLUCINOL BIOSYNTHESIS GENE phIA IN Pseudomonas fluorescens STRAIN CHAO UNDER GNOTOBIOTIC CONDITIONS

Pseudomonas fluorescens CHAO carrying reporter gene phi A - lacZ was used to monitor the influence of bean plant age on the expression of 2, 4-diacetylphloroglucinol biosynthesis genes in gnotobiotic system. The results revealed that bean plant age had a significant effect on reporter gene expression. Gene expression was not detected 45 min after planting pregerminated seeds according to units per 107 CFU. phIA - lacZ gene expression was significantly increased three days after planting the pregerminated seeds in comparison to 45 min after planting, remained at this level within five days and increased again during 14 days but this increase was not significantly different (P^D.05). Reporter gene expression based on units per g rhizosphere was not detected 45 min after planting but it increased significantly after three days. Gene expression increased by 20% from the third day to the fifth day of planting pregerminated seeds, reached at the level of the third day at seventh day and increased by 38% at the 14th day of plant growth. Bean rhizosphere colonization by CHAO carrying the reporter gene was in agreement with phIA - ʹlacZ gene expression based on units per g rhizosphere. Rhizosphere colonization was increased from 0.7xlO7 CFU/g rhizosphere in 45 min after planting to 7.7><107 CFU/g rhizosphere at the third day. Rhizosphere colonization was increased by 100% at fifth day in comparison to that of the third day, remained at the same level at the 7th day and peaked at the 14th day.