The potential of nitrogen-fixing (NF) bacteria to form a symbiotic relationship with leguminous plants and fix atmospheric nitrogen has been exploited in the field to meet the nitrogen requirement of the latter. This phenomenon provides an alternative to the use of the nitrogenous fertiliser whose excessive and imbalanced use over the decades has contributed to green house emission (N2O) and underground water leaching. Recently, it was observed that non-leguminous plants like rice, sugarcane, wheat and maize form an extended niche for various species of NF bacteria. These bacteria thrive within the plant, successfully colonizing roots, stems and leaves. During the association, the invading bacteria benefit the acquired host with a marked increase in plant growth, vigor and yield. With increasing population, the demand of non-leguminous plant products is growing. In this regard, the richness of NF flora within non-leguminous plants and extent of their interaction with the host definitely shows a ray of hope in developing an ecofriendly alternative to the nitrogenous fertilisers. In this review, we have discussed the association of NF bacteria with various non-leguminous plants emphasizing on their potential to promote host plant growth and yield. In addition, plant growth-promoting traits observed in these NF bacteria and their mode of interaction with the host plant have been described briefly.

Induction of heat shock proteins (HSPs) helps cells to survive severe hyperthermal stress and removes toxic unfolded proteins. At the same time, the cap‐dependent translation of global cellular mRNA is inhibited, due to the loss of function of eukaryotic initiation factor (eIF)4F complex. It has been previously reported that, following heat shock, HSP27 binds to the insoluble granules of eIF4G and impedes its association with cytoplasmic poly(A)‐binding protein (PABP) 1 and eIF4E. In the studies reported here, in addition to heat shock, we have included results of our investigation on the association between eIF4G, PABP1 and HSP27 during recovery from heat shock, when cap‐dependent mRNA translation resumes. We showed here that in the heat‐shocked cells, the PABP1–eIF4G complex dissociated, and both polypeptides translocated with the HSP27 to the nucleus. During recovery after heat shock, PABP1 and eIF4G were redistributed into the cytoplasm and colocalized with each other. In addition, PABP1 expression was upregulated and its translation efficiency was increased during the recovery period, possibly to meet additional demands on the translation machinery. HSP27 remained associated with the eIF4G–PABP1 complex during recovery from heat shock. Therefore, our results raise the possibility that the association of HSP27 with eIF4G may not be sufficient to suppress cap‐dependent translation during heat shock. In addition, we provide evidence that the terminal oligopyrimidine cis‐element of PABP1 mRNA is responsible for the preferential increase of PABP1 mRNA translation in cells undergoing recovery from heat shock.

Regulation of gene expression at the post-transcriptional level such as control of mRNA translation and stability is of fundamental importance because it allows cells to respond quickly to external signals, and change protein synthesis without new transcriptional activity. As such, control of translation and stability of mRNA play crucial roles in a variety of cellular processes, including regulating normal cellular growth, embryogenesis and neuronal plasticity. Consequently, misregulation of mRNA translation or degradation can be associated with a number of human diseases, such as cancer and diabetes. Studies have shown that the cytoplasmic poly (A)-binding protein (PABP) plays a crucial role in regulating both translation and stability of eukaryotic mRNA.

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