Abstract
Abstract The HAIRY MERISTEM (HAM) gene family encodes Type I and II GRAS domain transcriptional regulators in plants. Type II HAMs, predominantly expressed in meristems and regulated by microRNA171, are essential for maintaining undifferentiated meristems, a role conserved across various species. Conversely, the functions of Type I HAMs have been less characterized. In this study, we investigated the role of SlHAM4, a Type I HAM in tomato. CRISPR-induced SlHAM4 loss-of-function mutations (slham4CR) resulted in shoot and fruit abnormalities, which were fully reversed by reintroducing SlHAM4, driven by its native promoter, into the mutant background. Mutant abnormalities included simpler leaves and increased anthocyanin pigmentation in the leaf and sepal primordia, reminiscent of phenotypes observed in certain Arabidopsis mutants with compromised phloem. In addition, slham4CR plants produced significantly smaller fruits with a subset developing catface-like scars, attributed to tears that occurred in the pericarp of setting fruits. Using a GUS reporter gene driven by the native SlHAM4 promoter, we found that SlHAM4 is predominantly expressed in phloem tissues. Consistent with this, transcriptome analysis of mutant anthesis ovaries revealed specific downregulation of genes implicated in phloem development and function, particularly those expressed in companion cells. However, histological analysis showed no obvious abnormalities in phloem vasculature. Taken together, our data suggest that SlHAM4 plays a role in shoot and fruit development likely by regulating genes essential for phloem function.
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Claims 11
Claim · model-written summary
CRISPR-induced loss-of-function of SlHAM4 caused shoot and fruit abnormalities in tomato.
- Taxon
- tomato
Solanum lycopersicume0 - Treatment
- CRISPR-induced SlHAM4 loss-of-function mutationse1
- Gene
- SlHAM4e1
- Outcome
- shoot and fruit abnormalitiese1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a Type I HAM in tomato”
e1“CRISPR-induced SlHAM4 loss-of-function mutations (slham4CR) resulted in shoot and fruit abnormalities, which were fully reversed by reintroducing SlHAM4, driven by its native promoter, into the mutant background”
Claim · model-written summary
Reintroducing SlHAM4 under its native promoter into the mutant fully reversed the shoot and fruit abnormalities.
- Taxon
- tomatoSolanum lycopersicume0
- Treatment
- reintroducing SlHAM4, driven by its native promoter, into the mutant backgrounde1
- Gene
- SlHAM4e1
- Outcome
- shoot and fruit abnormalitiese1
- Direction
- fully reversede1
- Comparator
- mutant backgrounde1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a Type I HAM in tomato”
e1“CRISPR-induced SlHAM4 loss-of-function mutations (slham4CR) resulted in shoot and fruit abnormalities, which were fully reversed by reintroducing SlHAM4, driven by its native promoter, into the mutant background”
Claim · model-written summary
Mutant tomato plants had simpler leaves.
- Taxon
- tomatoSolanum lycopersicume0
- Treatment
- Mutante2
- Outcome
- simpler leavese2
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a Type I HAM in tomato”
e2“Mutant abnormalities included simpler leaves and increased anthocyanin pigmentation in the leaf and sepal primordia”
Claim · model-written summary
Mutant tomato plants had increased anthocyanin pigmentation in leaf and sepal primordia.
- Taxon
- tomatoSolanum lycopersicume0
- Organ / stage
- leaf and sepal primordiae2
- Treatment
- Mutante2
- Outcome
- anthocyanin pigmentation in the leaf and sepal primordiae2
- Direction
- increasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a Type I HAM in tomato”
e2“Mutant abnormalities included simpler leaves and increased anthocyanin pigmentation in the leaf and sepal primordia”
Claim · model-written summary
slham4CR plants produced significantly smaller fruits.
- Taxon
- tomatoSolanum lycopersicume0
- Treatment
- slham4CRe3
- Outcome
- fruitse3
- Direction
- smallere3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a Type I HAM in tomato”
e3“In addition, slham4CR plants produced significantly smaller fruits with a subset developing catface-like scars, attributed to tears that occurred in the pericarp of setting fruits”
Claim · model-written summary
A subset of slham4CR fruits developed catface-like scars.
- Taxon
- tomatoSolanum lycopersicume0
- Treatment
- slham4CRe3
- Outcome
- catface-like scarse3
- Qualifier
- with a subset developinge3
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a Type I HAM in tomato”
e3“In addition, slham4CR plants produced significantly smaller fruits with a subset developing catface-like scars, attributed to tears that occurred in the pericarp of setting fruits”
Claim · model-written summary
The catface-like scars were attributed to tears in the pericarp of setting fruits.
- Taxon
- tomatoSolanum lycopersicume0
- Outcome
- catface-like scarse3
- Qualifier
- tears that occurred in the pericarp of setting fruitse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a Type I HAM in tomato”
e3“In addition, slham4CR plants produced significantly smaller fruits with a subset developing catface-like scars, attributed to tears that occurred in the pericarp of setting fruits”
Claim · model-written summary
SlHAM4 is predominantly expressed in phloem tissues.
- Taxon
- tomatoSolanum lycopersicume0
- Organ / stage
- phloem tissuese4
- Gene
- SlHAM4e4
- Outcome
- predominantly expressede4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a Type I HAM in tomato”
e4“Using a GUS reporter gene driven by the native SlHAM4 promoter, we found that SlHAM4 is predominantly expressed in phloem tissues”
Claim · model-written summary
Transcriptome analysis of mutant anthesis ovaries showed downregulation of genes for phloem development and function, particularly in companion cells.
- Taxon
- tomatoSolanum lycopersicume0
- Organ / stage
- anthesis ovariese5
- Treatment
- mutante5
- Outcome
- genes implicated in phloem development and functione5
- Direction
- downregulatione5
- Qualifier
- particularly those expressed in companion cellse5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a Type I HAM in tomato”
e5“transcriptome analysis of mutant anthesis ovaries revealed specific downregulation of genes implicated in phloem development and function, particularly those expressed in companion cells”
Claim · model-written summary
Histological analysis showed no obvious abnormalities in phloem vasculature of the mutant.
- Taxon
- tomatoSolanum lycopersicume0
- Organ / stage
- phloem vasculaturee6
- Outcome
- obvious abnormalities in phloem vasculaturee6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a Type I HAM in tomato”
e6“histological analysis showed no obvious abnormalities in phloem vasculature”
Claim · model-written summary
SlHAM4 likely plays a role in shoot and fruit development by regulating genes essential for phloem function.
- Taxon
- tomatoSolanum lycopersicume0
- Gene
- SlHAM4e7
- Outcome
- shoot and fruit developmente7
- Qualifier
- likely by regulating genes essential for phloem functione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a Type I HAM in tomato”
e7“SlHAM4 plays a role in shoot and fruit development likely by regulating genes essential for phloem function”