Abstract
The SWEET4 gene plays a crucial role in regulating grain size. However, in barley, the relationship between HvSWEET4 expression and grain size remains unexamined, and the transcriptional regulation of SWEET4 during grain development is still largely unexplored. In this study, we employed two genetically unrelated six-rowed hulless barley varieties from the Qinghai–Tibetan Plateau, Beiqing3 (large grain) and 3917 (small grain), which showed marked differences in grain size. By integrating their phenotypic data and transcriptome profiles, we analyzed the expression patterns of HvSWEET4 during grain development, its correlation with grain traits, and the transcriptional regulation mechanism of HvSWEET4. We found that the two varieties exhibited distinct HvSWEET4 expression patterns: Beiqing3, which had higher HvSWEET4 expression, initiated grain transport tissue development earlier than 3917. Compared to wild-type plants, lines overexpressing HvSWEET4 exhibited significantly increased grain length, width, thickness, and weight. Both varieties shared an identical HvSWEET4 coding sequence, displayed subtle differences in the promoter region, and maintained low methylation levels. Weighted gene co‐expression network analysis (WGCNA) indicated that the co‐expressed transcription factor modules highly correlated with HvSWEET4 , as well as their core transcription factors, differed between the two varieties. Differences were also observed in both the expression levels of these core transcription factors and their binding sites within the promoter region. These findings suggest distinct patterns of HvSWEET4 transcriptional regulation during grain development between the two genotypes, providing valuable insights into the molecular mechanisms of HvSWEET4 in grain size regulation and highlighting its potential utility in barley breeding.
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Claims 8
Claim · model-written summary
Beiqing3 showed higher HvSWEET4 expression and earlier grain transport tissue development than 3917.
- Material
- Beiqing3e0
- Gene
- HvSWEET4e0
- Outcome
- grain transport tissue developmente0
- Direction
- earliere0
- Comparator
- 3917e0
Not reportedTaxon
Verbatim
e0“Beiqing3, which had higher HvSWEET4 expression, initiated grain transport tissue development earlier than 3917.”
Claim · model-written summary
HvSWEET4 overexpression significantly increased barley grain length, width and thickness relative to wild type.
- Treatment
- overexpressing HvSWEET4e0
- Gene
- HvSWEET4e0
- Outcome
- grain length, width, thicknesse0
- Direction
- increasede0
- Comparator
- wild-type plantse0
Not reportedTaxon
Verbatim
e0“Compared to wild-type plants, lines overexpressing HvSWEET4 exhibited significantly increased grain length, width, thickness, and weight.”
Claim · model-written summary
HvSWEET4 overexpression significantly increased barley grain weight relative to wild type.
- Treatment
- overexpressing HvSWEET4e0
- Gene
- HvSWEET4e0
- Outcome
- weighte0
- Direction
- increasede0
- Comparator
- wild-type plantse0
Not reportedTaxon
Verbatim
e0“Compared to wild-type plants, lines overexpressing HvSWEET4 exhibited significantly increased grain length, width, thickness, and weight.”
Claim · model-written summary
The two barley varieties shared the same HvSWEET4 coding sequence.
Not reportedTaxon
Verbatim
e0“Both varieties shared an identical HvSWEET4 coding sequence, displayed subtle differences in the promoter region, and maintained low methylation levels.”
Claim · model-written summary
The two varieties differed subtly in the HvSWEET4 promoter region.
Not reportedTaxon
Verbatim
e0“Both varieties shared an identical HvSWEET4 coding sequence, displayed subtle differences in the promoter region, and maintained low methylation levels.”
Claim · model-written summary
Both varieties maintained low methylation levels.
Not reportedTaxon
Verbatim
e0“Both varieties shared an identical HvSWEET4 coding sequence, displayed subtle differences in the promoter region, and maintained low methylation levels.”
Claim · model-written summary
HvSWEET4-correlated transcription factor modules and core transcription factors differed between the varieties.
- Material
- two varietiese0
- Gene
- HvSWEET4e0
- Outcome
- co‐expressed transcription factor modulese0
- Direction
- differede0
Not reportedTaxon
Verbatim
e0“the co‐expressed transcription factor modules highly correlated with HvSWEET4 , as well as their core transcription factors, differed between the two varieties.”
Claim · model-written summary
Core transcription factor expression levels and promoter binding sites differed between the varieties.
- Gene
- core transcription factorse0
- Outcome
- expression levelse0
- Qualifier
- binding sites within the promoter regione0
Not reportedTaxon
Verbatim
e0“Differences were also observed in both the expression levels of these core transcription factors and their binding sites within the promoter region.”