Field evaluation of PGP Bacillus sp. strain D5 native to Crocus sativus, in traditional and non traditional areas, and mining of PGP genes from its genome

Abstract

Native Bacillus sp. strain D5 coded as (Bar D5) has been isolated from the saffron corm that showed plant growth promotion (PGP) properties and also inhibits the growth of corm rot causing Fusarium oxysporum R1 (Fox R1) in-vitro. Bar D5 was more efficient PGP bacterium in comparison to earlier reported native bio-formulations by our group. Pot assays and field evaluation of Bar D5 confirmed its in-vivo efficacy for PGP traits and biocontrol activity as well. Pot trials were followed by field trials at traditional (Kishtwar) and non-traditional (R.S Pura) saffron cultivation areas in Jammu and Kashmir. At both places, Bar D5 bio-formulation treatment led to the increase in root number & length, shoot number & length, flower number and number & weight of daughter corms. Additionally, it also decreased the corm rot disease incidence significantly. Priming of corms with bio-formulation resulted in the reduction of pathogenic fungal load by three fold at the depth of corm sowing from ground level. The shelf life/viability of Bar D5 based bio-formulation was found to be 52% (viable spores) for one year at room temperature. Draft genome sequence of Bar D5 revealed the presence of genes necessary for PGP and biocontrol activity. Further, confirmation of gene sequences and annotation was done by amplification, re-sequencing and mapping of PGP and biocontrol genes on draft genome. Bar D5 based bio-formulation can be provided to companies/researchers interested in saffron cultivation or bio-formulation production for commercial exploitation, since saffron is grown as revenue crop across continents. The present study bridges the gap between genomics and its field application.

Plant Growth-Promoting Activity of Bacillus sp. PG-8 Isolated From Fermented Panchagavya and Its Effect on the Growth of Arachis hypogea

“…Various Bacillus sp. have been reported for multiple PGP activities such as IAA, GA, EPS production, and P solubilization (Bonatelli et al, 2020;Miljaković et al, 2020;Magotra et al, 2021). As PG-8 shows Secondary Screening of Bacillus sp.…”

Diversity of Rhizo-Bacteriome of Crocus sativus Grown at Various Geographical Locations and Cataloging of Putative PGPRs

“…The bacteriome and mycobiome of saffron rhizosphere were, for the first time, reported by our group (Ambardar et al, 2014(Ambardar et al, , 2016. In addition, PGPBs were isolated and evaluated in the course of the study (Ambardar and Vakhlu, 2013;Ambardar, 2014;Kour et al, 2018;Magotra et al, 2021). Recently, the cormosphere bacteriome of saffron was compared across the geographical locations from India and Morocco and preliminary data suggests that the microbiome is location specific and simultaneously, there is a core microbiome that is common to all locations (Bhagat et al, 2021).…”

“…The rhizosphere microbiome's contribution to plants has been acknowledged by giving it the title of "plant's second genome" (Ofek-Lalzar et al, 2014;Yin et al, 2020). Plant growth promotion by Plant growth promoting bacteria (PGPBs) has been reported in various plants such as in rice (Chauhan et al, 2019), wheat (Çakmakçı et al, 2017), maize (Zerrouk et al, 2019), tomato (Cordero et al, 2018), soya bean (De Gregorio et al, 2017) and saffron (Ambardar and Vakhlu, 2013;Ambardar, 2014;Ambardar et al, 2014Ambardar et al, , 2016Kour et al, 2018;Magotra et al, 2021).…”

Insights from the analysis of draft genome sequence of Crocus sativus L.

“…Some of the recently sequenced and assembled plant genomes are rice [ 1 ], maize [ 2 ], asparagus [ 3 ], wheat [ 4 ] and tea [ 5 ] etc., however the genome of the plants belonging to Crocus genus or Iridaceae family, have not been reported so far. Saffron (C. sativus) referred as 'Golden Condiment' is world's most expensive spice costing about 70,000 INR/pound, with medicinal properties and cosmetic uses [ 6 ]. More than 150 volatile and aroma-yielding compounds contribute to the flavor, color, and aroma of the saffron spice, wherein the main chemical constituents in the stigma of saffron are crocin, crocetin, picrocrocin, and safranal [ 7 ].…”