CHARACTERIZATION OF Frankia spp. ASSOCIATED WITH NON-LEGUMINOUS NITROGEN-FIXING PLANTS OF WESTERN HIMALAYA
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Date
2018-03
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UHF,NAUNI
Abstract
ABSTRACT
In recent years, land degradation has increased considerably due to demographic pressure and climatic
factors which has resulted in reduction of biodiversity, soil fertility and crop productivity. To overcome the
problems of lack of soil fertility in degraded areas, fast growing nitrogen fixing actinorhizal plants are being
considered for plantation programme. The studies on actinorhizal associations with prominent non-leguminous
species of mid and high hills i.e. Casuarina equisetifolia and Alnus nitida were conducted during 2014-2017.
The studies revealed that Casuarina samples harboured more actinobacterial population in root nodules
compared to Alnus. Among different media tried, Defined Propionate Minimal (DPM) medium with pyruvate as
carbon source was most suitable for the growth of actinobacteria. A total of 33 isolates from both the species
were isolated from Solan (mid hills) and Kullu (high hills) districts of Himachal Pradesh. Out of these 33
isolates, only 10 isolates exhibited maximum plant growth promoting traits viz. phosphate solubilization (250.0-
379.2 μg/ml), HCN production, growth on nitrogen free medium, auxin production (15.2-59.1 μg/ml) and
siderophore production (44.2-90.2% siderophore unit) as well as antagonism against Fusarium oxysporum,
Pythium sp., Rhizoctonia solani and Phytophthora sp. The phenotypic characterization of the isolates showing
branched hyphae bearing sporangia, vesicle like structures, non-turbidity of liquid medium and formation of
nodules in plant infection tests confirmed their identity with Frankia. The molecular characterization of Inter
Transcribed Spacer (ITS) region with selected primers was successful for three isolates (ANG10, ANG11 and
CG1). It revealed the similarity of two isolates i.e. ANG10 and ANG11 with Micromonospora sp. (88% and
90%, respectively) and in 23S region with Frankia sp. (91% and 91%, respectively). The ITS region of CG1
isolate showed similarity with Verrucosispora sp. (98%) and in 23S region with Frankia sp. (93%). The
sequence similarity was less with Frankia sp., which necessitates the identification of these isolates to be
verified with whole genome sequencing. The effect of application of selected isolates on plant growth and soil
parameters indicated that inoculation with CG1 isolate for Casuarina equisetifolia and ANG11 isolate for Alnus
nitida led to significant increase in shoot-root length, total biomass, total NPK content and their uptake and
available NPK content in soil over uninoculated control. Hence, these isolates have enormous potential to be
used as multifunctional biofertilizer for enhanced growth of actinorhizal plants and to sustain soil health under
mid and high hills of Himachal Pradesh.
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