The phosphate transporter (PHT) family of proteins plays an imperative role in regulating phosphorus (P) acquisition as well as in translocation from the soil into cells and organs. Phosphorus is an essential macronutrient required for plant life that is not readily available to crops, and resources are diminishing rapidly because of the huge needs of global agriculture. In this study, 23 ShPHT genes were identified in the sugarcane (Saccharum spp.) genome through a comprehensive genome-wide in silico analysis. Phylogeny, gene structure, and conserved motif analysis of PHT genes in sugarcane (ShPHTs) indicated five subfamilies (PHT1-4 and PHO1 subfamily). Gene ontology (GO) analysis revealed that the ShPHT genes were largely involved in phosphate ion transport, phosphate starvation, stimulus response, stress response, and symporter activity. Gene expression analysis under salinity stress confirmed strong induction of PHT genes in wild genotype sugarcane (IND99-907). PHT1-1, PHT1-2, and PHT1-3 members were notably up-regulated in roots under salt stress. The upstream region of PHT genes contained PHR1-binding sites (P1BS), MYB-type, and WRKY- type binding elements. Overall, the present study paves the way for a deeper understanding of the evolution of sugarcane PHT genes and their role in salinity and Pi stress tolerance in sugarcane.

A total of sixteen accessions of Tripidium arundinaceum (Retz.) Welker, Voronts. & E.A. Kellogg (previously known as Erianthus arundinaceus (Retz.) Jeswiet) were evaluated for salinity tolerance at the bud germination stage by irrigating with 175 mM salinized Hoagland solution in perlite-sand hydroponics. Six accessions, IND99-907, IND01-1134, IND01-1136, IK76-48, and Bethuadahari, were germinated with healthy roots as compared to other accessions. These six accessions were further evaluated for morphological, physiological, and root anatomical parameters for different levels of salinity stress at the formative phase. Young leaf elongation was ceased after the fourth and twelfth day in Co 97010 and Co 86032, respectively, at 175 mM of salinity stress. The growth of young leaves in Co 97010 and Co 86032 was observed up to 25 mM of salinity stress only, whereas in T. arundinaceum accessions viz., IND99-907 and Bethuadahari, growth was recorded even at 175 mM. Lignification of cell walls, thickening of protoxylems, and vacuolization of cortex regions were observed in Co 97010, Co 86032, Bethuadahari, and IND01-1134 as compared to the normal anatomical structures in IND99-907. The accession IND99-907 recorded the lowest Na/K ratio, followed by IND99-1136 at 175 mM of salinity stress. The accession IND99-907 was identified as a salinity-tolerant genotype and suitable for utilization in the sugarcane crop improvement programmes.