Hd5;DTH8

Gene Details

MSU gene ID: LOC_Os08g07740
RAPdb gene ID: Os08g0174500
Gene Symbol: Hd5 DTH8 Ghd8 OsHAP3H LHD1 EF8 CAR8 OsNF-YB11
Genome: MSU7 , IRGSP-1.0
Species: Oryza sativa

Functional Descriptions

Map-based cloning reveals that DTH8 encodes a putative HAP3 subunit of the CCAAT-box-binding transcription factor and the complementary experiment increased significantly days to heading, plant height, and number of grains per panicle in CSSL61 (a chromosome segment substitution line that carries the nonfunctional DTH8 allele) with the Asominori functional DTH8 allele under long-day conditions.
Here, we report the cloning and characterization of Ghd8, a major QTL with pleiotropic effects on grain yield, heading date, and plant height.
Here, through map-based cloning, we identified a major quantitative trait loci (QTL) LHD1 (Late Heading Date 1), an allele of DTH8/Ghd8, which controls the late heading date of wild rice and encodes a putative HAP3/NF-YB/CBF-A subunit of the CCAAT-box-binding transcription factor.
LHD1, an allele of DTH8/Ghd8, controls late heading date in common wild rice (Oryza rufipogon).
Taken together, these data indicate that DTH8 probably plays an important role in the signal network of photoperiodic flowering as a novel suppressor as well as in the regulation of plant height and yield potential.
DTH8 suppresses flowering in rice, influencing plant height and yield potential simultaneously.
A major QTL, Ghd8, plays pleiotropic roles in regulating grain productivity, plant height, and heading date in rice.
Meanwhile, the transcription of DTH8 has been proved to be independent of Ghd7 and Hd1, and the natural mutation of this gene caused weak photoperiod sensitivity and shorter plant height.
Ghd8 up-regulated MOC1, a key gene controlling tillering and branching; this increased the number of tillers, primary and secondary branches, thus producing 50% more grains per plant.
Our results demonstrated the important roles of Ghd8 in rice yield formation and flowering, as well as its opposite functions in flowering between rice and Arabidopsis under long-day conditions.
The Hd5 gene controlling heading date (flowering time) generated variations in heading date among cultivars adapted to Hokkaido, where is the northernmost region of Japan and one of the northern limits of rice cultivation in the world.
By regulating Ehd1, RFT1, and Hd3a, Ghd8 delayed flowering under long-day conditions, but promoted flowering under short-day conditions.
The ectopic expression of Ghd8 in Arabidopsis caused early flowering by 10 d-a situation similar to the one observed by its homolog AtHAP3b, when compared to wild-type under long-day conditions; these findings indicate the conserved function of Ghd8 and AtHAP3b in flowering in Arabidopsis.
The quantitative real-time PCR assay revealed that DTH8 could down-regulate the transcriptions of Ehd1 (for Early heading date1) and Hd3a (for Heading date3a; a rice ortholog of FLOWERING LOCUS T) under long-day conditions.
By using near-isogenic lines with functional or deficient alleles of several rice flowering-time genes, we observed significant digenetic interactions between Hd16 and four other flowering-time genes (Ghd7, Hd1, DTH8 and Hd2).
We also found that LHD1 could down-regulate the expression of several floral transition activators such as Ehd1, Hd3a and RFT1 under long-day conditions, but not under short-day conditions.
The association of the Hd5 genotype with heading date and genetical analysis clearly showed that the loss-of-function Hd5 has an important role in exhibiting earlier heading among a local population in Hokkaido.
These results demonstrated that Hd5 plays roles not only in generating early heading in variations of heading date among a local population in Hokkaido, but also in extremely early heading for adaptation to northern limits of rice cultivation.
Roles of the Hd5 gene controlling heading date for adaptation to the northern limits of rice cultivation.
This indicates that LHD1 may delay flowering by repressing the expression of Ehd1, Hd3a and RFT1 under long-day conditions.
Sequence analysis revealed that several variants in the coding region of LHD1 were correlated with a late heading date, and a further complementary study successfully rescued the phenotype.
Distinct distribution of the loss-of-function Hd5 revealed that this mutation event of the 19-bp deletion occurred in a local landrace Bouzu and that this mutation may have been selected as an early-heading variety in rice breeding programs in Hokkaido in the early 1900s.
Our data indicate that EF8 plays an important role in rice photoperiodic flowering pathway as well as yield potential and chlorophyll biogenesis and will be an important target for rice breeding programs.
EF8 encodes a putative HAP3 subunit of the CCAAT-box-binding transcription factor, which is localized to the nucleus.
EF8 is involved in photoperiodic flowering pathway and chlorophyll biogenesis in rice.
Fine mapping suggested that CAR8 encodes a putative Heme Activator Protein 3 (OsHAP3) subunit of a CCAAT-box-binding transcription factor called OsHAP3H.
This indicates that CAR8 affects multiple physiological aspects relating to photosynthesis.
The detailed analysis of molecular functions of CAR8 would help to understand the association between photosynthesis and flowering and demonstrate specific genetic mechanisms that can be exploited to improve photosynthesis in rice and potentially other crops.
A key variant in the cis-regulatory element of flowering gene Ghd8 associated with cold tolerance in rice.
Transgenic analyses revealed that higher expression levels of Ghd8 delayed heading date and enhanced cold tolerance in rice.
Ghd8 and Ghd7, two major flowering genes, have similar functions and large pleiotropic effects in controlling the heading date, plant height and grain yield of rice.
The results of this study help to elucidate the genetic and molecular bases of Ghd8 and Ghd7 interactions, indicating that Ghd8 acts upstream of Ghd7 to activate its transcription, which inhibits Hd3a expression and thus affects flowering time and rice adaptation.
However, under LD conditions, Hd1 promotes Ghd7 expression and is recruited by Ghd7 and/or DTH8 to form repressive complexes that collaboratively suppress the Ehd1-Hd3a/RFT1 pathway to block heading, but under SD conditions Hd1 competes with the complexes to promote Hd3a/RFT1 expression, playing a tradeoff relationship with PS flowering.
Hd1, Ghd7, and DTH8 synergistically determine the rice heading date and yield-related agronomic traits.
In this study, we systematically analyze the heading date, PS, and agronomic traits of eight homozygous lines with various combinations of Hd1, Ghd7, and DTH8 alleles in the prr37 background under long-day (LD) and short-day (SD) conditions, respectively.
DTH8 up-regulates the transcription of RFT1, Hd3a, GHD7, MOC1, and RCN1 in IR64 at the pre-flowering stage and plays a role in early flowering, increased number of tillers, enhanced panicle branching, and improved tolerance towards drought and salinity stress at the reproductive stage.
Taken together, DTH8 is a positive regulator of the network of genes related to early flowering/heading, higher yield, as well as salinity and drought stress tolerance, thus, enabling the crops to adapt to a wide range of climatic conditions.
We demonstrate DTH8 to be positively influencing the yield, heading date, and stress tolerance in IR64.
In addition, DTH8 overexpressing transgenic lines showed favorable physiological parameters causing less yield penalty under stress than the WT plants.
DTH8 overexpression induces early flowering, boosts yield, and improves stress recovery in rice cv IR64.
The amino acid residue E96 orf Ghd8 is crucial for the formation of the flowering repression complex Ghd7-Ghd8-OsHAP5C in rice.
MutMap analysis revealed that SOG7 is allelic to Ghd8 and delayed flowering under long-day (LD) conditions.

Functional Keywords

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Gene Resources

Sequences

cDNA Sequence

>LOC_Os08g07740.1
TCTCAATTCTCATAAAATAAATCAATCCCTTGCCTAGACTCCAATAACAAAAGAAAATGTAATACTTCCTTCGGTCATTAGTATATGTTAGTATAAATTAAATAATTAAACACCTTAAACAATATTTTTTCGTCGTAGTTTGATCATCACCTAAGATTTTTTAGTCTTTTCAAAATGATCATCAGCTAACAAGTGTATCTTTATTTATTTGTGCAAGAAGTAAATGAGCATCATTGAATGCGCTGCACACATGTAATGCAAACAACCAAGTTAATTTTTATTGGTGCAACGGCGCGCACTATTTAAAACGTGACGCAATGCAGCGATAGAGCACCTTGATAGATAAGAATTAATTTCAGCATGATGTAGATTTTGTTATCCTTAATCTCTACTCACTTTGCATAGGTAATAAATTAAACCGCTGAACTATTACTACATGGTTTACATGAAAGGTGATCGGGTAGGGACGAGAATGTCGCGACACACATAATATATATAGTAGCGTCCTTATGTTTGCTTTGTGTCCGCATCGATACCGTCTTCCCACTCGCATCTCCTCACCTCCTTTCCTTCTTTAAAAGGAGAGCATCACCACTCCATCCTCAACTCCCATAACCTCCCCCTTCTCTCTCTCTCTAACTACACACTCTCTCTCTAGCTAGCTAGCTAGCTATAGCTAGTGTTGTTAGCTTCACATGAAGAGTAGGAAGAGCTATGGGCACTTGCTGAGCCCGGTGGGCAGCCCGCCGTTGGACAACGAGTCCGGCGAGGCGGCGGCGGCGGCTGCGGCTGGCGGCGGCGGCTGCGGGAGCAGCGCCGGGTATGTCGTCTACGGCGGCGGCGGCGGTGGGGACTCGCCGGCGAAGGAGCAGGACAGGTTCCTGCCGATCGCGAACGTGAGCCGCATCATGAAGCGGTCGCTGCCGGCGAACGCCAAGATCTCCAAGGAGTCGAAGGAGACGGTGCAGGAGTGCGTGTCGGAGTTCATCAGCTTCGTTACAGGCGAGGCCTCCGACAAGTGCCAGCGCGAGAAGCGGAAGACCATCAACGGCGACGACCTCCTCTGGGCCATGACCACGCTGGGGTTCGAGGCCTACGTCGGCCCGCTCAAGTCCTACCTCAACCGCTACCGCGAGGCCGAGGGCGAGAAGGCCGACGTGCTCGGCGGCGCCGGCGGCGCCGCCGCGGCGCGCCACGGCGAGGGCGGTTGCTGCGGCGGCGGCGGCGGCGGCGCCGATGGCGTCGTCATCGACGGGCATTACCCGCTCGCCGGCGGCCTGTCACACTCACACCATGGTCATCAGCAGCAGGACGGCGGCGGCGACGTCGGGCTCATGATGGGCGGCGGCGACGCCGGCGTCGGGTACAACGCCGGGGCCGGGTCGACGACGACGGCGTTCTACGCGCCGGCGGCGACGGCGGCGTCAGGGAACAAGGCGTACTGCGGCGGCGACGGGTCGAGGGTGATGGAGTTCGAGGGCATCGGCGGCGAGGAGGAGAGCGGAGGCGGCGGCGGCGGCGGCGAGAGGGGGTTCGCCGGCCACCTCCATGGCGTGCAATGGTTTAGACTAAAGAGGAATACTAATTAGCTAGCTAGGCACACGCGTAGTTTTATTATTACTTAATTACCGCGTTAATTAATTGTTGATGCTGATGCTGTTTAAAATTGATTCTCCTTTTGCATGAAATGTTTGATGGTATGGTTTAAAATTGAAGAA

CDS Sequence

>LOC_Os08g07740.1
ATGAAGAGTAGGAAGAGCTATGGGCACTTGCTGAGCCCGGTGGGCAGCCCGCCGTTGGACAACGAGTCCGGCGAGGCGGCGGCGGCGGCTGCGGCTGGCGGCGGCGGCTGCGGGAGCAGCGCCGGGTATGTCGTCTACGGCGGCGGCGGCGGTGGGGACTCGCCGGCGAAGGAGCAGGACAGGTTCCTGCCGATCGCGAACGTGAGCCGCATCATGAAGCGGTCGCTGCCGGCGAACGCCAAGATCTCCAAGGAGTCGAAGGAGACGGTGCAGGAGTGCGTGTCGGAGTTCATCAGCTTCGTTACAGGCGAGGCCTCCGACAAGTGCCAGCGCGAGAAGCGGAAGACCATCAACGGCGACGACCTCCTCTGGGCCATGACCACGCTGGGGTTCGAGGCCTACGTCGGCCCGCTCAAGTCCTACCTCAACCGCTACCGCGAGGCCGAGGGCGAGAAGGCCGACGTGCTCGGCGGCGCCGGCGGCGCCGCCGCGGCGCGCCACGGCGAGGGCGGTTGCTGCGGCGGCGGCGGCGGCGGCGCCGATGGCGTCGTCATCGACGGGCATTACCCGCTCGCCGGCGGCCTGTCACACTCACACCATGGTCATCAGCAGCAGGACGGCGGCGGCGACGTCGGGCTCATGATGGGCGGCGGCGACGCCGGCGTCGGGTACAACGCCGGGGCCGGGTCGACGACGACGGCGTTCTACGCGCCGGCGGCGACGGCGGCGTCAGGGAACAAGGCGTACTGCGGCGGCGACGGGTCGAGGGTGATGGAGTTCGAGGGCATCGGCGGCGAGGAGGAGAGCGGAGGCGGCGGCGGCGGCGGCGAGAGGGGGTTCGCCGGCCACCTCCATGGCGTGCAATGGTTTAGACTAAAGAGGAATACTAATTAG

Protein Sequence

>LOC_Os08g07740.1
MKSRKSYGHLLSPVGSPPLDNESGEAAAAAAAGGGGCGSSAGYVVYGGGGGGDSPAKEQDRFLPIANVSRIMKRSLPANAKISKESKETVQECVSEFISFVTGEASDKCQREKRKTINGDDLLWAMTTLGFEAYVGPLKSYLNRYREAEGEKADVLGGAGGAAAARHGEGGCCGGGGGGADGVVIDGHYPLAGGLSHSHHGHQQQDGGGDVGLMMGGGDAGVGYNAGAGSTTTAFYAPAATAASGNKAYCGGDGSRVMEFEGIGGEEESGGGGGGGERGFAGHLHGVQWFRLKRNTN*