Abstract
Phenylalanine ammonia-lyase (PAL) catalyzes the first reaction in the biosynthesis from phenylalanine of a wide variety of phenylpropanoid natural products including lignin, flavonoid pigments, and phytoalexins. In bean (Phaseolus vulgaris L.), PAL is encoded by a family of three genes. We show here by RNase protection with gene-specific probes that these genes are expressed differentially during development and in response to different environmental cues. While all three genes are expressed at high levels in roots, only PAL1 and PAL2 are expressed in shoots and only PAL1 is expressed in leaves. Strikingly, PAL2 is expressed at very high levels in petals, where PAL1 is only very weakly expressed and PAL3 is not expressed. All three genes are induced by mechanical wounding of hypocotyls, but fungal infection only activates PAL1 and PAL3. Illumination of etiolated hypocotyls activates PAL1 and PAL2 but not PAL3. Corresponding differential patterns of synthesis of specific PAL polypeptide isoforms were observed by two-dimensional gel electrophoretic analysis of in vitro translation products encoded by RNA isolated from hypocotyls stimulated by light, wounding, or infection. The specific isoforms encoded by transcripts of the three PAL genes were identified by inhibition of synthesis in vitro with gene-specific anti-sense transcripts followed by comparative two-dimensional gel electrophoretic analysis of the pattern of translation products. These data indicate that selective expression of PAL genes encoding functional variants is governed by a complex set of regulatory networks for developmental and environmental control of phenylpropanoid biosynthesis.
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Claims 9
Claim · model-written summary
All three bean PAL genes are expressed at high levels in roots.
Not reportedTaxon
Verbatim
e0“all three genes are expressed at high levels in roots”
Claim · model-written summary
PAL1 and PAL2, but not PAL3, are expressed in bean shoots.
Not reportedTaxon
Verbatim
e0“only PAL1 and PAL2 are expressed in shoots”
Claim · model-written summary
Only PAL1 is expressed in bean leaves.
Not reportedTaxon
Verbatim
e0“only PAL1 is expressed in leaves”
Claim · model-written summary
PAL2 is very highly expressed in petals, whereas PAL1 is weakly expressed and PAL3 is not expressed.
- Organ / stage
- petalse0
- Gene
- PAL2e0
- Outcome
- expressed at very high levelse0
- Qualifier
- PAL1 is only very weakly expressed and PAL3 is not expressede0
Not reportedTaxon
Verbatim
e0“PAL2 is expressed at very high levels in petals, where PAL1 is only very weakly expressed and PAL3 is not expressed”
Claim · model-written summary
Mechanical wounding induces all three PAL genes in bean hypocotyls.
Not reportedTaxonComparator
Verbatim
e0“All three genes are induced by mechanical wounding of hypocotyls”
Claim · model-written summary
Fungal infection activates PAL1 and PAL3 in bean hypocotyls.
Not reportedTaxonComparator
Verbatim
e0“fungal infection only activates PAL1 and PAL3”
Claim · model-written summary
Illumination activates PAL1 and PAL2, but not PAL3, in etiolated bean hypocotyls.
- Organ / stage
- etiolated hypocotylse0
- Treatment
- Illuminatione0
- Outcome
- PAL1 and PAL2e0
- Direction
- activatese0
- Qualifier
- but not PAL3e0
Not reportedTaxonComparator
Verbatim
e0“Illumination of etiolated hypocotyls activates PAL1 and PAL2 but not PAL3”
Claim · model-written summary
PAL polypeptide isoforms showed differential synthesis patterns after light, wounding or infection stimulation.
Not reportedTaxon
Verbatim
e0“Corresponding differential patterns of synthesis of specific PAL polypeptide isoforms were observed by two-dimensional gel electrophoretic analysis of in vitro translation products encoded by RNA isolated from hypocotyls stimulated by light, wounding, or infection”
Claim · model-written summary
Gene-specific antisense inhibition identified isoforms encoded by transcripts of the three PAL genes.
Not reportedComparatorValue
Verbatim
e0“The specific isoforms encoded by transcripts of the three PAL genes were identified by inhibition of synthesis in vitro with gene-specific anti-sense transcripts followed by comparative two-dimensional gel electrophoretic analysis of the pattern of translation products”