Phosphate supply influenced the growth, yield and expression of PHT1 family phosphate transporters in seven millets
Phosphate starvation altered the root morphology and phosphate uptake with the induction of PHT1 family transporter genes in root and shoot tissues of seven millets.
Millets are nutrient-rich cereals majorly cultivated in Asia and Africa. Foxtail millet (FoxM), pearl millet (PeaM), finger millet (FinM), kodo millet (KodM), little millet (LitM), proso millet (ProM), and barnyard millet (BarM) were examined for the influence of external phosphorous (P) supply on phenotypic traits, P uptake, yield, and PHosphate Transporter1 (PHT1) family gene expression. Millet seedlings grown under low Pi condition (LPC) produced significantly lower mean values for all traits except for lateral root length (LRL) and lateral root number (LRN) which were increased under LPC. Under LPC, seed weight (SW) also reduced by > 75% and had significantly lower levels of total P (TP) and Pi contents in leaf and root tissues. Expression dynamics of 12 PHT1 family (PHT1;1–1;12) transporters genes were analyzed in 7 millets. PHT1;2 has been found to be a constitutive transporter gene in all millets. Under LPC, root tissues showed the overexpression of PHT1;2, 1;3, 1;4 and 1;9 in FoxM, PHT1;1, 1;2, 1;3, 1;4, 1;8 and 1;10 in PeaM, PHT1;2 and 1;3 in FinM and ProM and PHT1;3, 1;6 and 1;11 in BarM. In leaf, LPC induced the expression of PHT1;3, 1;4 and 1;6 in FoxM, PHT1;2, 1;3, 1;4 and 1;8 in PeaM, PHT1;2, 1;3 and 1;4 in FinM and KodM, PHT1;2 in LitM and PHT1;4 in ProM and BarnM. This comprehensive study on the influence of P in phenotype, physiology, and molecular responses may help to improve the P uptake and its use efficiency of millets in future.
KeywordsGene expression Millets Phenotyping Phosphorous Phosphate transporter 1 (PHT1) Seed yield
High/low Pi condition
Lateral root length/number
Phosphate transporter 1
Primary root length
Root/shoot dry weight
Seed weight (yield)
The authors thank the International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, India and Tamil Nadu Agricultural University, Coimbatore, India for providing millet seeds. Prof Alison Baker, Centre for Plant Sciences, University of Leeds, UK for supplying foxtail millet PHT1 gene-specific primers.
This work was funded by Loyola College-Times of India Grant (No: 7LCTOI14ERI001) and European Union through a Marie Curie International Incoming Fellowship to SAC (Fellowship Number: FP7-People-2-11-IIF-Prposal-921672-Acronym IMPACT). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Compliance with ethical standards
Conflicts of interest
The authors declare that they have no competing interests.
- Basirat M, Malboobi MA, Mousavi A, Asgharzadeh A, Samavat S (2011) Effects of phosphorous supply on growth, phosphate distribution and expression of transporter genes in tomato plants. Aust J Crop Sci 5:537–543Google Scholar
- Ceasar SA (2018) Genome-wide identification and in silco analysis of PHT1 family genes and proteins in Setaria viridis: a best model to study the nutrient transport in millets. Plant Genome 12:1–9Google Scholar
- Ceasar SA, Baker A, Muench SP, Ignacimuthu S, Baldwin SA (2016) The conservation of phosphate-binding residues among PHT1 transporters suggests that distinct transport affinities are unlikely to result from differences in the phosphate-binding site. Biochem Soc Trans 44:1541–1548CrossRefGoogle Scholar
- Kumar A, Metwal M, Kaur S, Gupta AK, Puranik S, Singh S, Singh M, Gupta S, Babu B, Sood S (2016) Nutraceutical value of finger millet [Eleusine coracana (L.) Gaertn.], and their improvement using omics approaches. Front Plant Sci 7:e934Google Scholar
- Liu F, Xu Y, Jiang H, Jiang C, Du Y, Gong C, Wang W, Zhu S, Han G, Cheng B (2016) Systematic identification, evolution and expression analysis of the Zea mays PHT1 gene family reveals several new members involved in root colonization by arbuscular mycorrhizal fungi. Int J Mol Sci 17:930–948CrossRefGoogle Scholar
- Mahamood J, Abayomi Y, Aduloju M (2009) Comparative growth and grain yield responses of soybean genotypes to phosphorous fertilizer application. Afr J Biotechnol 8:1030–1036Google Scholar
- Ramakrishnan M, Ceasar SA, Vinod K, Duraipandiyan V, Krishna TA, Upadhyaya HD, Al-Dhabi N, Ignacimuthu S (2017) Identification of putative QTLs for seedling stage phosphorus starvation response in finger millet (Eleusine coracana L. Gaertn.) by association mapping and cross species synteny analysis. PLoS One 12:e0183261CrossRefGoogle Scholar
- Teng W, Zhao YY, Zhao XQ, He X, Ma WY, Deng Y, Chen XP, Tong YP (2017) Genome-wide identification, characterization, and expression analysis of PHT1 phosphate transporters in wheat. Front Plant Sci 8:543Google Scholar