Microorganisms play very important role in biogeochemical cycle in soil, which reflects the plant growth and influence the agricultural production. Phosphate solubilizing microorganisms (PSM) are very important to the plants under phosphorus stress. As we know, Phosphorus is one of the essential macronutrients, along with nitrogen, required by the plants for their vital functions and survival. But, the efficiency of phosphatic fertilizers is very low due to their fixation in both acidic and alkaline soils which are predominant in India. Therefore, the inoculation of mineral phosphate solubilizers and other useful microbial inoculants in these soils would play an important role to restore the overall balance of nutrients and health of the soil to sustain it for posterity. The molecular genetics and mechanism of mineral phosphate solubilization and their efficiency in releasing phosphates for plant uptake is seemingly different and varies with microorganisms. Hence, the isolation and characterization of superior strains of mineral phosphate solubilizers to suit different soil types is imperative. These phosphate-solubilizing bacteria have the capacity to convert the insoluble forms of phosphorus into its soluble fo rm, wh i ch u l t i mat el y get s avai l ab l e t o p l an t s, a p h en o men o n o ft en referred t o as mi n eral p h o sp h at e so l u b i l i sat i o n . Th e combination of chemical fertilizers with this beneficial microorganism is also one of the ways to increase the agricultural y i e l d w i t h o u t l o s s o f n u t r i e n t s . M o r e o v e r , t h e d e v e l o p m e n t s o f c o m m e r c i a l b i o i n o c u l a n t s w i l l b e g r e a t l y a c c e p t e d b y farmers an d wi l l h el p t o mai n t ai n agri cu l t u re su st ai n ab i l i t y. Th e p resen t art i cl e d escri b es t h e p ro gress o f research i n t h i s area and future insights about use of such biophores in agriculture.

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Pseudomonas syringae-secreted HopA1 effectors are important determinants in host range expansion and increased pathogenicity. Their recent acquisitions via horizontal gene transfer in several non-pathogenic Pseudomonas strains worldwide have caused alarming increase in their virulence capabilities. In Arabidopsis thaliana, RESISTANCE TO PSEUDOMONAS SYRINGAE 6 (RPS6) gene confers effector-triggered immunity (ETI) against HopA1pss derived from P. syringae pv. syringae strain 61. Surprisingly, a closely related HopA1pst from the tomato pathovar evades immune detection. These responsive differences in planta between the two HopA1s represents a unique system to study pathogen adaptation skills and host-jumps. However, molecular understanding of HopA1′s contribution to overall virulence remain undeciphered. Here, we show that immune-suppressive functions of HopA1pst are more potent than HopA1pss. In the resistance-compromised ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) null-mutant, transcriptomic changes associated with HopA1pss-elicited ETI are still induced and carry resemblance to PAMP-triggered immunity (PTI) signatures. Enrichment of HopA1pss interactome identifies proteins with regulatory roles in post-transcriptional and translational processes. With our demonstration here that both HopA1 suppress reporter-gene translations in vitro imply that the above effector-associations with plant target carry inhibitory consequences. Overall, with our results here we unravel possible virulence role(s) of HopA1 in suppressing PTI and provide newer insights into its detection in resistant plants.

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Rapid adaptation of plants to developmental or physiological cues is facilitated by specific receptors that transduce the signals mostly via post-translational modification (PTM) cascades of downstream partners. Reversible covalent attachment of SMALL UBIQUITIN-LIKE MODIFIER (SUMO), a process termed as SUMOylation, influence growth, development and adaptation of plants to various stresses. Strong regulatory mechanisms maintain the steady-state SUMOylome and mutants with SUMOylation disturbances display mis-primed immunity often with growth consequences. Identity of the SUMO-substrates undergoing SUMOylation changes during defences however remain largely unknown. Here we exploit either the auto-immune property of an Arabidopsis mutant or defense responses induced in wild-type plants against Pseudomonas syringae pv tomato (PstDC3000) to enrich and identify SUMO1-substrates. Our results demonstrate massive enhancement of SUMO1-conjugates due to increased SUMOylation efficiencies during defense responses. Of the 261 proteins we identify, 29 have been previously implicated in immune-associated processes. Role of others expand to diverse cellular roles indicating massive readjustments the SUMOylome alterations may cause during induction of immunity. Overall, our study highlights the complexities of a plant immune network and identifies multiple SUMO-substrates that may orchestrate the signalling.