Institutional Publications

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Author: search.filters.author.Mani, BalajiHas files: Yes

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    Rice phosphate transporter reduces the low phosphate response through jasmonate signaling
    (Oxford University Press, 2026) Mani, Balaji; Maurya, Kanika; Verma, Lokesh; Gupta, Priya; Kohli, Pawandeep Singh; Gupta, Gagan; Jaskolowski, Aime; Poirier, Yves; Giri, Jitender
    Phosphorus (P) is an essential macronutrient for plant growth, and its deficiency severely limits crop productivity. The PHOSPHATE1 (PHO1) protein family, defined by an N-terminal SPX domain, four transmembrane (4TM) domains, and a C-terminal EXS domain, mediates phosphate (Pi) loading into the xylem for root-to-shoot transport. In rice, OsPHO1;2 is critical for Pi export, and loss-of-function mutants exhibit severe growth retardation and Pi deficiency symptoms despite sufficient external Pi. To dissect the functional contributions of PHO1 domains beyond Pi transport, we generated CRISPR/Cas9 rice lines expressing either the EXS domain containing part of the SPX domain (S-EXS) or the 4TM+EXS domains (T-EXS) of OsPHO1;2. Phenotypic analyses under Pi-sufficient and Pi-deficient conditions revealed that S-EXS lines displayed improved early growth compared to ospho1;2 mutants, despite similar shoot Pi levels. These plants exhibited reduced jasmonic acid accumulation and attenuated phosphate starvation responses, resembling wild-type hormone profiles. In contrast, T-EXS lines mirrored the growth defects of ospho1;2 mutants. Transcriptome profiling confirmed that defense and phosphate starvation pathways were less activated in S-EXS lines relative to mutants. However, both S-EXS and T-EXS lines retained seed development defects and reduced seed phosphorus content, consistent with ospho1;2 phenotypes. Heterozygous plants carrying one functional OsPHO1;2 allele exhibited normal growth and seed development, confirming the recessive nature of the mutation. Collectively, these findings demonstrate that the S-EXS domain of OsPHO1;2 promotes plant growth independently of Pi transport by modulating jasmonate signaling and suppressing phosphate starvation responses. This highlights a signaling role for PHO1 domains, offering new insights into Pi homeostasis and potential strategies for breeding Pi-efficient crops.
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    Editing cis-elements of OsPHO1;2 improved phosphate transport and yield in rice
    (John Wiley & Sons, 2025) Maurya, Kanika; Mani, Balaji; Singh, Bhagat; Sirohi, Ujjwal; Jaskolowski, Aime; Sharma, Sandeep; Tatiparthi, Harsha Vardhan; Mangrauthia, Satendra Kumar; Pandey, Renu; Poirier, Yves; Giri, Jitender
    Increasing grain yield is the primary goal of crop improvement, which is globally affected by the low availability of soil phosphate (Pi). Overexpressing Pi transporters to enhance Pi uptake often results in Pi toxicity and growth retardation. Despite advances in genetic engineering, targeting the cis-regulatory motifs of Pi transporters remains underexplored for understanding plant mechanisms and improving Pi status. Here, we demonstrate that the excision of the transcription inhibitor motif from the promoter of the Pi transporter OsPHO1;2 enhances its expression and increases root-to-shoot Pi transport, leading to improved grain yield. Through in silico and DNA-protein interaction studies, we show the role of the OsWRKY6 transcription factor in negatively regulating OsPHO1;2 expression by binding to the cis-regulatory element (W-box) present in its promoter. The oswrky6 knockout lines exhibit higher OsPHO1;2 expression and improved shoot Pi levels. Furthermore, we engineered the OsPHO1;2 promoter to precisely remove the W-box and enhance OsPHO1;2 expression. Phenotypic and physiological evaluations at the vegetative stage indicate that OsPHO1;2 promoter-edited (OsPHO1;2:PE) lines have increased shoot length, plant biomass and greater root-to-shoot Pi export under both low and normal P conditions. Notably, the 33P uptake assay reveals that OsPHO1;2:PE lines display enhanced root Pi uptake, supported by higher expression of root-associated Pi transporters (OsPHTs). An extensive agronomic assessment shows that OsPHO1;2:PE lines achieve increased seed and panicle numbers, thereby raising yield without affecting seed quality. Our findings provide valuable insights into the potential of promoter editing to improve Pi use and enhance crop yield.
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    Chickpea (Cicer arietinum) PHO1 family members function redundantly in Pi transport and root nodulation
    (Elsevier B.V., 2024) Mani, Balaji; Maurya, Kanika; Kohli, Pawandeep Singh; Giri, Jitender
    Phosphorus (P), a macronutrient, plays key roles in plant growth, development, and yield. Phosphate (Pi) transporters (PHTs) and PHOSPHATE1 (PHO1) are central to Pi acquisition and distribution. Potentially, PHO1 is also involved in signal transduction under low P. The current study was designed to identify and functionally characterize the PHO1 gene family in chickpea (CaPHO1s). Five CaPHO1 genes were identified through a comprehensive genome-wide search. Phylogenetically, CaPHO1s formed two clades, and protein sequence analyses confirmed the presence of conserved domains. CaPHO1s are expressed in different plant organs including root nodules and are induced by Pi-limiting conditions. Functional complementation of atpho1 mutant with three CaPHO1 members, CaPHO1, CaPHO1;like, and CaPHO1;H1, independently demonstrated their role in root to shoot Pi transport, and their redundant functions. To further validate this, we raised independent RNA-interference (RNAi) lines of CaPHO1, CaPHO1;like, and CaPHO1;H1 along with triple mutant line in chickpea. While single gene RNAi lines behaved just like WT, triple knock-down RNAi lines (capho1/like/h1) showed reduced shoot growth and shoot Pi content. Lastly, we showed that CaPHO1s are involved in root nodule development and Pi content. Our findings suggest that CaPHO1 members function redundantly in root to shoot Pi export and root nodule development in chickpea.
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    Root hair-specific transcriptome reveals response to low phosphorus in Cicer arietinum
    (Frontiers Media S.A., 2022) Kohli, Pawandeep Singh; Pazhamala, Lekha T; Mani, Balaji; Thakur, Jitendra K.; Giri, Jitender
    Root hairs (RH) are a single-cell extension of root epidermal cells. In low phosphorus (LP) availability, RH length and density increase thus expanding the total root surface area for phosphate (Pi) acquisition. However, details on genes involved in RH development and response to LP are missing in an agronomically important leguminous crop, chickpea. To elucidate this response in chickpea, we performed tissue-specific RNA-sequencing and analyzed the transcriptome modulation for RH and root without RH (Root-RH) under LP. Root hair initiation and cellular differentiation genes like RSL TFs and ROPGEFs are upregulated in Root-RH, explaining denser, and ectopic RH in LP. In RH, genes involved in tip growth processes and phytohormonal biosynthesis like cell wall synthesis and loosening (cellulose synthase A catalytic subunit, CaEXPA2, CaGRP2, and CaXTH2), cytoskeleton/vesicle transport, and ethylene biosynthesis are upregulated. Besides RH development, genes involved in LP responses like lipid and/or pectin P remobilization and acid phosphatases are induced in these tissues summarizing a complete molecular response to LP. Further, RH displayed preferential enrichment of processes involved in symbiotic interactions, which provide an additional benefit during LP. In conclusion, RH shows a multi-faceted response that starts with molecular changes for epidermal cell differentiation and RH initiation in Root-RH and later induction of tip growth and various LP responses in elongated RH.
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    OsJAZ9 is involved in water-deficit stress tolerance by regulating leaf width and stomatal density in rice
    (Elsevier B.V., 2021) Singh, Ajit Pal; Mani, Balaji; Giri, Jitender
    Drought stress poses a severe threat to grain yield in rice. Our previous report demonstrated the role of OsJAZ9 in potassium homeostasis by modulating Jasmonic Acid (JA) signalling. While both potassium (K) and JA are known to have an important role in drought stress response, JA's repressor, i.e., JAZs' role in drought stress, remains elusive. Here we report that OsJAZ9 plays a critical role in rice water-deficit stress tolerance via influencing JA and ABA signalling. Overexpression of OsJAZ9 led to the enhanced ABA and JA levels. Our data further revealed that exogenous JA application antagonises the ABA-mediated inhibition of seed germination. Further, OsJAZ9 overexpression reduces leaf width and stomata density, leading to lower leaf transpiration rates than WT. This reduced transpiration and higher K content as osmoticum improved the water-deficit stress tolerance in OsJAZ9 overexpression lines. On the contrary, OsJAZ9 RNAi lines displayed enhanced sensitivity towards water-deficit stress. Our data provide new insights on the role of JA signalling repressors in rice response to water-deficit stress.