Plant Molecular Biology

, Volume 59, Issue 6, pp 945–964

Tissue-Specific Expression and Drought Responsiveness of Cell-Wall Invertase Genes of Rice at Flowering

  • X. M. Ji
  • M. Raveendran
  • R. Oane
  • A. Ismail
  • R. Lafitte
  • R. Bruskiewich
  • S. H. Cheng
  • J. Bennett
Article

DOI: 10.1007/s11103-005-2415-8

Cite this article as:
Ji, X.M., Raveendran, M., Oane, R. et al. Plant Mol Biol (2005) 59: 945. doi:10.1007/s11103-005-2415-8
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Abstract

Drought stress near heading reduces grain yield in rice cultivars by inhibiting processes such as anther dehiscence and panicle exsertion. Because cell-wall invertases play an important role in carbon allocation to developing organs, we examined the tissue-specific expression and drought sensitivity of the corresponding genes (OsCIN1-9) at heading in the widely grown cultivar IR64. OsCIN1-5,8 were expressed to varying degrees in flag leaf, panicle, anthers and peduncle at 1 day before heading (1 DBH). When water was withheld for 2 days starting 3 DBH, anthesis and peduncle elongation were halted. At the same time, transcript levels for OsCIN1-5,8 genes were all markedly down-regulated in anthers and/or peduncles but were not affected in flag leaves. Re-watering allowed anthesis and peduncle elongation to proceed and restored expression of OsCIN1-5,8. We conclude that cell-wall invertase genes, as a class, respond rapidly to water deficit in anthers and peduncles and through a reduction in sink strength help to coordinate a delay in anthesis and heading. By contrast, vacuolar invertase OsVIN2 was up-regulated by drought stress in flag leaves, panicles, anthers and peduncles. Although OsCIN1-3,5,8 were active in the peduncle, only OsCIN2 was expressed strongly and preferentially at the base, where cell division and cell elongation occur. OsCIN2 was expressed principally in the primary and secondary vascular systems, consistent with a role in diverting sucrose from the phloem to the dividing and expanding cells of the peduncle, whereas the less abundant OsCIN1,3,5,8 transcripts were found principally in parenchyma cells. The OsCIN2 transcript levels in the base were highest at 1 DBH, when rapid peduncle elongation began. Drought stress halted peduncle elongation and reduced OsCIN2 transcript level to 8% of the control level. On re-watering, peduncle elongation was restored and OsCIN2 transcript level recovered to 24% of the control. The abscisic acid (ABA) level of peduncles increased 7-fold on drought stress and returned to the control level on re-watering. Detached peduncles floated on water elongated little and lost all OsCIN2 transcripts, but on 50–100 μM GA3 they elongated rapidly and maintained high OsCIN2 transcript levels. ABA antagonized both peduncle elongation and maintenance of OsCIN2 transcript levels. We conclude that this antagonism is a potential intervention point for breeding strategies directed at enhancing panicle exsertion during or after drought stress at heading.

Key words

abscisic acid anther gibberellin peduncle starch vacuole 

Abbreviations

ABA

abscisic acid

BCIP/NBT

5-bromo-4-chloro-3-indoxyl phosphate/nitroblue tetrazolium chloride

DAH

days after heading

DAPI

4’,6-diamidino-2-phenylindole

DBH

days before heading

DEPC

diethylpyrocarbonate

GA

gibberellic acid

IRRI

International Rice Research Institute

NTE

0.5M NaCl, 0.1M Tris–HCl, pH 7.5, 0.05M EDTA, pH 8.0

OsCIN

Oryza sativa cell-wall invertase

OsNIN

Oryza sativa neutral/alkaline invertase

OsVIN

Oryza sativa vacuolar invertase

RT–PCR

reverse transcription–polymerase chain reaction

SSPE

150 mM NaCl, 10 mM NaH2PO4, 1 mM EDTA, pH 7.4

Copyright information

© Springer 2005

Authors and Affiliations

  • X. M. Ji
    • 1
    • 2
  • M. Raveendran
    • 1
    • 3
  • R. Oane
    • 1
  • A. Ismail
    • 1
  • R. Lafitte
    • 1
  • R. Bruskiewich
    • 1
  • S. H. Cheng
    • 2
  • J. Bennett
    • 1
  1. 1.Plant Breeding, Genetics and Biochemistry Division, International Rice Research InstituteMetro ManilaPhilippines
  2. 2.China National Rice Research InstituteHangzhouChina
  3. 3.Tamil Nadu Agricultural UniversityCoimbatoreIndia

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