Sugar-responsive gene expression, invertase activity, and senescence in aborting maize ovaries at low water potentials

John McLaughlin, John S. Boyer

Research output: Contribution to journalArticle

89 Citations (Scopus)

Abstract

• Background and Aims: Ovary abortion can occur in maize (Zea mays) if water deficits lower the water potential (ψw) sufficiently to inhibit photosynthesis around the time of pollination. The abortion decreases kernel number. The present work explored the activity of ovary acid invertases and their genes, together with other genes for sucrose-processing enzymes, when this kind of abortion occurred. Cytological evidence suggested that senescence may have been initiated after 2 or 3 d of low ψw, and the expression of some likely senescence genes was also determined. • Methods: Ovary abortion was assessed at kernel maturity. Acid invertase activities were localized in vivo and in situ. Time courses for mRNA abundance were measured with real time PCR. Sucrose was fed to the stems to vary the sugar flux. • Key Results: Many kernels developed in controls but most aborted when ψw became low. Ovary invertase was active in controls but severely inhibited at low ψw for cell wall-bound forms in vivo and soluble forms in situ. All ovary genes for sucrose processing enzymes were rapidly down-regulated at low ψw except for a gene for invertase inhibitor peptide that appeared to be constitutively expressed. Some ovary genes for senescence were subsequently up-regulated (RIP2 and PLD1). In some genes, these regulatory changes were reversed by feeding sucrose to the stems. Abortion was partially prevented by feeding sucrose. • Conclusions: A general response to low ψw in maize ovaries was an early down-regulation of genes for sucrose processing enzymes followed by up-regulation of some genes involved in senescence. Because some of these genes were sucrose responsive, the partial prevention of abortion with sucrose feeding may have been caused in part by the differential sugar-responsiveness of these genes. The late up-regulation of senescence genes may have caused the irreversibility of abortion.

Original languageEnglish (US)
Pages (from-to)675-689
Number of pages15
JournalAnnals of Botany
Volume94
Issue number5
DOIs
StatePublished - Dec 1 2004
Externally publishedYes

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beta-Fructofuranosidase
Zea mays
Ovary
Gene Expression
Sucrose
Water
Genes
Up-Regulation
Enzymes
Pollination
Photosynthesis
Regulator Genes
Cell Wall
Real-Time Polymerase Chain Reaction
Down-Regulation

All Science Journal Classification (ASJC) codes

  • Plant Science

Cite this

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title = "Sugar-responsive gene expression, invertase activity, and senescence in aborting maize ovaries at low water potentials",
abstract = "• Background and Aims: Ovary abortion can occur in maize (Zea mays) if water deficits lower the water potential (ψw) sufficiently to inhibit photosynthesis around the time of pollination. The abortion decreases kernel number. The present work explored the activity of ovary acid invertases and their genes, together with other genes for sucrose-processing enzymes, when this kind of abortion occurred. Cytological evidence suggested that senescence may have been initiated after 2 or 3 d of low ψw, and the expression of some likely senescence genes was also determined. • Methods: Ovary abortion was assessed at kernel maturity. Acid invertase activities were localized in vivo and in situ. Time courses for mRNA abundance were measured with real time PCR. Sucrose was fed to the stems to vary the sugar flux. • Key Results: Many kernels developed in controls but most aborted when ψw became low. Ovary invertase was active in controls but severely inhibited at low ψw for cell wall-bound forms in vivo and soluble forms in situ. All ovary genes for sucrose processing enzymes were rapidly down-regulated at low ψw except for a gene for invertase inhibitor peptide that appeared to be constitutively expressed. Some ovary genes for senescence were subsequently up-regulated (RIP2 and PLD1). In some genes, these regulatory changes were reversed by feeding sucrose to the stems. Abortion was partially prevented by feeding sucrose. • Conclusions: A general response to low ψw in maize ovaries was an early down-regulation of genes for sucrose processing enzymes followed by up-regulation of some genes involved in senescence. Because some of these genes were sucrose responsive, the partial prevention of abortion with sucrose feeding may have been caused in part by the differential sugar-responsiveness of these genes. The late up-regulation of senescence genes may have caused the irreversibility of abortion.",
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Sugar-responsive gene expression, invertase activity, and senescence in aborting maize ovaries at low water potentials. / McLaughlin, John; Boyer, John S.

In: Annals of Botany, Vol. 94, No. 5, 01.12.2004, p. 675-689.

Research output: Contribution to journalArticle

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AU - Boyer, John S.

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