Abstract
Heading date is a key agronomic trait that determines the seasonal and regional adaptability of rice varieties. Hd6 encodes the CK2α subunit, which regulates heading date in rice by phosphorylating florigen regulators. Loss-of-function mutants of Hd6 exhibit earlier heading under long-day conditions. To shorten the growth duration of the elite, tasty, late-season japonica cultivar Nanjing 46 (NJ46) and expand its cultivation range, the Hd6 gene in NJ46 was knocked out using CRISPR/Cas9- mediated gene editing. A target site was designed within the second exon of Hd6, and its specificity was validated by BLAST analysis. The expression vector pCAMBIA1305-Actin:Cas9-sgRNAHd6 was constructed and introduced into NJ46 callus via Agrobacterium-mediated transformation. Homozygous mutant lines without exogenous components were screened using PCR. The heading date, major agronomic traits, yield-related traits, and grain quality traits of these lines were evaluated in both central and northern Jiangsu and compared with those of local benchmark cultivars Nanjing 9108 (NJ9108) and Nanjing 518 (NJ518), respectively. In the T0 generation, 18 transgenic positive plants were obtained. In the T2 generation, three homozygous mutant lines with different mutation types and free of exogenous sequences were identified: NJ46-hd6ko-1 (TTGG deletion), NJ46-hd6ko-2 (25 bp deletion), and NJ46-hd6ko-3 (G deletion). Their heading dates were 21.1, 24.7, and 21.4 d earlier than that of NJ46, respectively. Among them, NJ46-hd6ko-3 showed similar heading date, theoretical yield, milled rice rate, amylose content, gel consistency, and taste value to NJ9108, but had a shorter plant height and a higher alkali spreading value, indicating superior overall performance and suitability for cultivation in the central Jiangsu region. NJ46-hd6ko-2 showed no significant differences in heading date, theoretical yield, or alkali spreading value compared to NJ518, but demonstrated significantly higher milled rice rate and taste value, along with a shorter plant height, suggesting enhanced overall traits and suitability for the northern Jiangsu region. By precisely editing the Hd6 gene in NJ46, we developed new elite, tasty japonica rice germplasms adapted to the central and northern Jiangsu ecological zones, thereby expanding the cultivation area for high-quality, palatable rice varieties.
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Claims 14
Claim · model-written summary
Eighteen transgenic positive plants were obtained in the T0 generation.
- Taxon
- rice
Oryza sativat0 - Organ / stage
- T0 generatione0
- Outcome
- transgenic positive plantse0
- Value
- 18e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“In the T0 generation, 18 transgenic positive plants were obtained.”
Claim · model-written summary
Three homozygous mutant lines without exogenous sequences were identified in the T2 generation.
- Taxon
- riceOryza sativat0
- Organ / stage
- T2 generatione0
- Gene
- NJ46-hd6ko-1e0
- Outcome
- three homozygous mutant linese0
- Value
- threee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“In the T2 generation, three homozygous mutant lines with different mutation types and free of exogenous sequences were identified: NJ46-hd6ko-1 (TTGG deletion), NJ46-hd6ko-2 (25 bp deletion), and NJ46-hd6ko-3 (G deletion).”
Claim · model-written summary
NJ46-hd6ko-1 headed 21.1 days earlier than NJ46.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-1e1
- Treatment
- TTGG deletione1
- Outcome
- heading datese0
- Direction
- earliere0
- Value
- 21.1e0
- Comparator
- NJ46e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“Their heading dates were 21.1, 24.7, and 21.4 d earlier than that of NJ46, respectively.”
e1“NJ46-hd6ko-1 (TTGG deletion)”
Claim · model-written summary
NJ46-hd6ko-2 headed 24.7 days earlier than NJ46.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-2e1
- Treatment
- 25 bp deletione1
- Outcome
- heading datese0
- Direction
- earliere0
- Value
- 24.7e0
- Comparator
- NJ46e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“Their heading dates were 21.1, 24.7, and 21.4 d earlier than that of NJ46, respectively.”
e1“NJ46-hd6ko-2 (25 bp deletion)”
Claim · model-written summary
NJ46-hd6ko-3 headed 21.4 days earlier than NJ46.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-3e1
- Treatment
- G deletione1
- Outcome
- heading datese0
- Direction
- earliere0
- Value
- 21.4 de0
- Comparator
- NJ46e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“Their heading dates were 21.1, 24.7, and 21.4 d earlier than that of NJ46, respectively.”
e1“NJ46-hd6ko-3 (G deletion)”
Claim · model-written summary
NJ46-hd6ko-3 matched NJ9108 in heading date, theoretical yield and milled rice rate.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-3e0
- Outcome
- heading date, theoretical yield, milled rice ratee0
- Direction
- similare0
- Comparator
- NJ9108e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“NJ46-hd6ko-3 showed similar heading date, theoretical yield, milled rice rate, amylose content, gel consistency, and taste value to NJ9108”
Claim · model-written summary
NJ46-hd6ko-3 matched NJ9108 in amylose content, gel consistency and taste value.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-3e0
- Outcome
- amylose content, gel consistency, and taste valuee0
- Direction
- similare0
- Comparator
- NJ9108e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“NJ46-hd6ko-3 showed similar heading date, theoretical yield, milled rice rate, amylose content, gel consistency, and taste value to NJ9108”
Claim · model-written summary
NJ46-hd6ko-3 was shorter than NJ9108.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-3e1
- Outcome
- plant heighte0
- Direction
- shortere0
- Comparator
- NJ9108e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“but had a shorter plant height and a higher alkali spreading value”
e1“NJ46-hd6ko-3 showed similar heading date, theoretical yield, milled rice rate, amylose content, gel consistency, and taste value to NJ9108”
Claim · model-written summary
NJ46-hd6ko-3 had a higher alkali spreading value than NJ9108.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-3e1
- Outcome
- alkali spreading valuee0
- Direction
- highere0
- Comparator
- NJ9108e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“but had a shorter plant height and a higher alkali spreading value”
e1“NJ46-hd6ko-3 showed similar heading date, theoretical yield, milled rice rate, amylose content, gel consistency, and taste value to NJ9108”
Claim · model-written summary
NJ46-hd6ko-2 did not differ significantly from NJ518 in heading date, theoretical yield or alkali spreading value.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-2e0
- Outcome
- heading date, theoretical yield, or alkali spreading valuee0
- Direction
- no significant differencese0
- Comparator
- NJ518e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“NJ46-hd6ko-2 showed no significant differences in heading date, theoretical yield, or alkali spreading value compared to NJ518”
Claim · model-written summary
NJ46-hd6ko-2 had significantly higher milled rice rate and taste value than NJ518.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-2e1
- Outcome
- milled rice rate and taste valuee0
- Direction
- highere0
- Comparator
- NJ518e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“but demonstrated significantly higher milled rice rate and taste value, along with a shorter plant height”
e1“NJ46-hd6ko-2 showed no significant differences in heading date, theoretical yield, or alkali spreading value compared to NJ518”
Claim · model-written summary
NJ46-hd6ko-2 was shorter than NJ518.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-2e1
- Outcome
- plant heighte0
- Direction
- shortere0
- Comparator
- NJ518e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“along with a shorter plant height”
e1“NJ46-hd6ko-2 showed no significant differences in heading date, theoretical yield, or alkali spreading value compared to NJ518”
Claim · model-written summary
The authors judged NJ46-hd6ko-3 suitable for central Jiangsu.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-3e1
- Outcome
- suitability for cultivatione0
- Setting
- central Jiangsu regione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“suitability for cultivation in the central Jiangsu region”
e1“NJ46-hd6ko-3 showed similar heading date”
Claim · model-written summary
The authors judged NJ46-hd6ko-2 suitable for northern Jiangsu.
- Taxon
- riceOryza sativat0
- Material
- NJ46-hd6ko-2e1
- Outcome
- suitabilitye0
- Setting
- northern Jiangsu regione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice”
e0“suitability for the northern Jiangsu region”
e1“NJ46-hd6ko-2 showed no significant differences”
The same questions in other papers
loss of function · phenology · Oryza sativa (rice)Positive and negative results
2 papers in the same direction as this paper · 13 in the opposite direction
- no effect
- negative
- negative
12 papers more in this group
See all 16 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.