Abstract:
Usages of isolated plant growth promoting rhizobacteria as biofertilizer is an effective
alternative for the sustainable agricultural practice to expand soil strength and to enhance the
crop productivity of selected monocot and dicot plant seedlings. The aim of the present
investigation is to explore a plant growth promoting bacteria with further employability of
biofertilizer production applying on selected economically important crops (Cumin - Cuminum
cyminum L., Rice - Oryza sativa, Mung - Vigna radiata L., Chickpea - Cicer arietinum L., and
Groundnut-Arachis hypogaea) at a seedling stage. Total 75 bacterial isolates were collected
from different region of Saurashtra, Gujarat state, India. Among them 41 morphologically
different bacterial colonies were isolated and further screened for their PGPR traits. For the
primary screening of selected bacterial isolates has been performed; IAA production,
phosphate solubilization, siderophore production, HCN production and ammonia production.
Among these 100% isolates were positive for ammonia production, 85.36% isolates were
positive for IAA production, 31.70% isolates were positive for HCN production, 17.07%
isolates were positive for phosphate solubilization, 9.75% isolates were positive for
siderophore production at 37℃ of incubation period. In primary screening 11 bacterial isolates
have showing PGPR properties but in quantitative screening of IAA & ammonia production,
out of 11 only 4 bacterial isolates (KS2, KC8, KC9 and KC11) having the potency of PGPR
traits. Bio-priming method was used for the seedling analysis. In current study to assess the
impact of 4 specific PGPR isolates on seedlings of monocot (Rice, Mung, Cumin) & dicot
(Groundnut, Chickpea) plants, we measured parameters like root and shoot length and no. of
leaves have been calculated at the interval of 15 days under controlled conditions employing
statistical analysis one factor at a time approach/CRD. Potent bacterial PGPR isolates were
identified through 16S rRNA sequencing data analysis revealed two genera: Bacillus sp. and
Proteus sp.Biological control agents are eco-friendly to prevent plant pathogens effectively. In
the present investigation four potent isolates were examined for their ability to confer disease
resistance against Fusarium sp induced wilt disease in monocot and dicot plant.In
vitro technique was employed to inspect the ability of potent bacterial isolates such as KS2,
KC8, KC9 and KC11 in order to control Fusarium sp. Result revealed by dual culture
interaction shows, the colony diameter of Fusarium sp. was significantly reduced when KS2, KC8, KC9 interact with individually and KC11. However, the strain KC9- Bacillus sp.
(OQ654027) had shown an antagonistic activity around 2.8mm found to be higher than other
recorded strains in present study, while, KC11 Proteus Columbae sp. (OQ652027) had found
to be recorded with an antagonistic activity around 2.3 mm against Fusarium sp. respectively.
The other two strains namely, KS2 (Proteus Columbae) and KC8 (Bacillus sp.) had
documented to show a decreased activity against the same strain as mentioned earlier. The two
strains namely KS2 and KC8 although are found to be recorded with plant growth promoting
activity but have not shown any significant antagonistic activity. The probable reason for the
surprising result for KS2 and KC8 can be due to the fact of absence of ISR which found to be
a strong reason for being an antagonistic agent.
