Abstract
Starch biosynthesis, a very critical event during pollen development, is not well understood in terms of gene regulation and intracellular controls. Using the rice HL‐type cytoplasmic male sterile (HL‐CMS) line with starch deficiency in pollen and two related male‐fertile lines ( Oryza sativa L.), we have studied two specific developmental stages: ‘early’, that is, before or during pollen mitosis I, without starch accumulation, and ‘late’, the actively starch‐filling postpollen mitosis I phase. Real‐time reverse transcription‐PCR analysis showed temporal changes in the expression patterns of six metabolic genes involved in the sucrose–starch pathway, i.e. sucrose synthase (EC 2.4.1.13), Rsus3 ; acid invertase (EC 3.2.1.26), OSINV2 ; phosphoglucomutase (EC 5.4.2.2), OsPGM ; uridine diphosphate‐glucose pyrophosphorylase (EC 2.7.7.9), OsUGP ; a subunit of adenosine diphosphate‐glucose pyrophosphorylase (AGPase) (EC 2.2.7.2), OsAGPL3 ; soluble starch synthase (EC 2.4.1.21), OsSSI and three transporter genes [sucrose transporter, OsSUT3 ; hexose transporter, OSMST7 and plasma membrane H + ‐adenosine triphosphatase (ATPase) (EC 3.6.1.35), OSA2 ]. Regarding metabolic enzyme activities, lower activity of sucrose synthase was detected at ‘late’ compared with ‘early’ stage in the three rice lines; invertase and other downstream enzymes had higher activities at ‘late’ stage in male‐fertile but not male‐sterile lines. Meanwhile, significantly reduced sugars and ATP levels were detected at ‘early’ and ‘late’ stages in male‐sterile compared with male‐fertile tissues. Furthermore, transgenic data showed that AGPase gene can stimulate starch accumulation in pollen of male‐sterile host lines, showing the importance of AGPase in the metabolic pathway. Taken together, these data suggest that the combined effects of the reduced energy supply and sugar levels in starch biosynthesis may lead to the observed temporal changes in gene expression, and eventually to pollen sterility.
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Claims 7
Claim · model-written summary
Nine sucrose–starch metabolic and transporter genes showed temporal expression changes during rice pollen maturation.
- Taxon
- Oryza sativa L.
Oryza sativae2 - Outcome
- temporal changes in the expression patternse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Real‐time reverse transcription‐PCR analysis showed temporal changes in the expression patterns of six metabolic genes involved in the sucrose–starch pathway”
e1“and three transporter genes”
e2“Oryza sativa L.”
Claim · model-written summary
Sucrose synthase activity was lower at the late than early stage in all three rice lines.
- Taxon
- riceOryza sativae0
- Organ / stage
- ‘late’e0
- Gene
- sucrose synthasee0
- Outcome
- activity of sucrose synthasee0
- Direction
- lowere0
- Comparator
- ‘early’ stagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“lower activity of sucrose synthase was detected at ‘late’ compared with ‘early’ stage in the three rice lines”
Claim · model-written summary
Invertase and downstream enzyme activities were higher at the late stage in fertile but not sterile rice lines.
- Taxon
- riceOryza sativae1
- Material
- male‐fertilee0
- Gene
- invertasee0
- Outcome
- invertase and other downstream enzymes had higher activitiese0
- Direction
- highere0
- Comparator
- male‐sterile linese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“invertase and other downstream enzymes had higher activities at ‘late’ stage in male‐fertile but not male‐sterile lines”
e1“rice HL‐type cytoplasmic male sterile (HL‐CMS) line”
Claim · model-written summary
Sugar levels were significantly reduced in sterile compared with fertile rice tissues at both stages.
- Taxon
- riceOryza sativae1
- Material
- male‐sterilee0
- Outcome
- sugarse0
- Direction
- reducede0
- Comparator
- male‐fertile tissuese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significantly reduced sugars and ATP levels were detected at ‘early’ and ‘late’ stages in male‐sterile compared with male‐fertile tissues”
e1“rice HL‐type cytoplasmic male sterile (HL‐CMS) line”
Claim · model-written summary
ATP levels were significantly reduced in sterile compared with fertile rice tissues at both stages.
- Taxon
- riceOryza sativae1
- Material
- male‐sterilee0
- Outcome
- ATP levelse0
- Direction
- reducede0
- Comparator
- male‐fertile tissuese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significantly reduced sugars and ATP levels were detected at ‘early’ and ‘late’ stages in male‐sterile compared with male‐fertile tissues”
e1“rice HL‐type cytoplasmic male sterile (HL‐CMS) line”
Claim · model-written summary
The AGPase gene stimulated starch accumulation in sterile rice pollen.
- Taxon
- riceOryza sativae1
- Treatment
- transgenice0
- Gene
- AGPase genee0
- Outcome
- starch accumulation in pollene0
- Direction
- stimulatee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic data showed that AGPase gene can stimulate starch accumulation in pollen of male‐sterile host lines”
e1“rice HL‐type cytoplasmic male sterile (HL‐CMS) line”
Claim · model-written summary
The authors suggest that reduced energy and sugar supply alters gene expression and ultimately causes pollen sterility.
- Taxon
- riceOryza sativae1
- Outcome
- pollen sterilitye0
- Qualifier
- reduced energy supply and sugar levelse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“combined effects of the reduced energy supply and sugar levels in starch biosynthesis may lead to the observed temporal changes in gene expression, and eventually to pollen sterility”
e1“rice HL‐type cytoplasmic male sterile (HL‐CMS) line”
The same questions in other papers
transgenic · quality: sugar starch · Oryza sativa (rice)Positive and negative results
1 paper in the same direction as this paper · 3 in the opposite direction
- negative
- negative
- no effect
1 paper more in this group
See all 5 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.