OsHIPL1, a hedgehog‐interacting protein‐like 1 protein, increases seed vigour in rice

Abstract

The cultivation of rice varieties with high seed vigour is vital for the direct seeding of rice, and the molecular basis of regulation of seed vigour remains elusive. Here, we cloned a new gene OsHIPL1, which encodes hedgehog-interacting protein-like 1 protein as a causal gene of the major QTL qSV3 for rice seed vigour. OsHIPL1 was mainly localized in the plasma membrane and nucleus. RNA sequencing (RNA-seq) revealed that the ABA-related genes were involved in the OsHIPL1 regulation of seed vigour in rice. The higher levels of endogenous ABA were measured in germinating seeds of OsHIPL1 mutants and NIL-qsv3 line compared to IR26 plants, with two up-regulated ABA biosynthesis genes (OsZEP and OsNCED4) and one down-regulated ABA catabolism gene OsABA8ox3. The expression of abscisic acid-insensitive 3 (OsABI3), OsABI4 and OsABI5 was significantly up-regulated in germinating seeds of OsHIPL1 mutants and NIL-qsv3 line compared to IR26 plants. These results indicate that the regulation of seed vigour of OsHIPL1 may be through modulating endogenous ABA levels and altering OsABIs expression during seed germination in rice. Meanwhile, we found that OsHIPL1 interacted with the aquaporin OsPIP1;1, then affected water uptake to promote rice seed germination. Based on analysis of singlenucleotide polymorphism data of rice accessions, we identified a Hap1 haplotype of OsHIPL1 that was positively correlated with seed germination. Our findings showed novel insights into the molecular mechanism of OsHIPL1 on seed vigour.

Insights into the Regulation of Rice Seed Storability by Seed Tissue-Specific Transcriptomic and Metabolic Profiling

“…In legumes, ABSCISIC ACID INSENSITIVE5 (ABI5) regulated late seed maturation by influencing longevity and RFO accumulation [53]. In rice, it was found that OsHIPL1 mutants, which regulated seed vigor, had higher levels of endogenous ABA in germinated seeds, with two ABA biosynthesis genes (OsZEP and OsNCED4) up-regulated and one ABA catabolism gene, OsABA8ox3 down-regulated [54]. Our study revealed that they might have a potential function in seed storability regulation by affecting hormone homeostasis.…”

Genome-wide association study reveals novel QTLs and candidate genes for seed vigor in rice

“…Physiological analysis revealed that qSE3 improved seed germination and seedling establishment against salinity stress through mediating seed physiological states, including increasing K + and Na + uptake, promoting abscisic acid (ABA) biosynthesis, and reducing reactive oxygen species (ROS) accumulation. Very recently, OsHIPL1 , which encodes a hedgehog-interacting protein-like 1 protein, was cloned as a causal gene for the major QTL qSV3 associated with rice SV ( He et al., 2022 ). And OsHIPL1 may play its role by modulating ABA levels and OsABIs expression during rice seed germination.…”

Transcriptome-Wide Characterization of Seed Aging in Rice: Identification of Specific Long-Lived mRNAs for Seed Longevity

“…ABA is the other major phytohormones in seed development and seed vigor regulations. It reported that OsHIPL1 protein may modulate endogenous ABA levels and altering OsABIs expression and interacts directly with OsPIP1;1 to affect seed vigor in rice ( He et al, 2022 ), we analyzed the expression of OsHIPL1 and OsPIP1;1 in the HL and LL varieties ( Supplementary Figures 5A,B ), unfortunately, their expression levels have no difference between two varieties, suggesting the differences between the reverse genetic method and the forward genetic method (e.g., transcriptomic analysis). We also identified several long-lived mRNAs with unknown functions, which might be the missed or omitted regulators in rice longevity.…”