Chlorophyll metabolism in pollinated vs. parthenocarpic fig fruits throughout development and ripening.
Expression of 13 genes encoding chlorophyll biosynthesis and degradation was evaluated. Chlorophyll degradation was differentially regulated in pollinated and parthenocarpic fig fruits, leading to earlier chlorophyll degradation in parthenocarpic fruits. Varieties of the common fig typically yield a commercial summer crop that requires no pollination, although it can be pollinated. Fig fruit pollination results in larger fruit size, greener skin and darker interior inflorescence color, and slows the ripening process compared to non-pollinated fruits. We evaluated the effect of pollination on chlorophyll content and levels of transcripts encoding enzymes of the chlorophyll metabolism in fruits of the common fig 'Brown Turkey'. We cloned and evaluated the expression of 13 different genes. All 13 genes showed high expression in the fruit skin, inflorescences and leaves, but extremely low expression in roots. Pollination delayed chlorophyll breakdown in the ripening fruit skin and inflorescences. This was correlated with the expression of genes encoding enzymes in the chlorophyll biosynthesis and degradation pathways. Expression of pheophorbide a oxygenase (PAO) was strongly negatively correlated with chlorophyll levels during ripening in pollinated fruits; along with its high expression levels in yellow leaves, this supports a pivotal role for PAO in chlorophyll degradation in figs. Normalizing expression levels of all chlorophyll metabolism genes in the pollinated and parthenocarpic fruit skin and inflorescences showed three synthesis (FcGluTR1, FcGluTR2 and FcCLS1) and three degradation (FcCLH1, FcCLH2 and FcRCCR1) genes with different temporal expression in the pollinated vs. parthenocarpic fruit skin and inflorescences. FcCAO also showed different expressions in the parthenocarpic fruit skin. Thus, chlorophyll degradation is differentially regulated in the pollinated and parthenocarpic fruit skin and inflorescences, leading to earlier and more sustained chlorophyll degradation in the parthenocarpic fruit.
Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel.|The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, 76100, Rehovot, Israel.
Yogev
Y
Rosianskey
Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel.
Yardena
Y
Dahan
Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel.
Sharawan
S
Yadav
Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel.
Zohar E
ZE
Freiman
Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel.
Shira
S
Milo-Cochavi
The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, P.O. Box 12, 76100, Rehovot, Israel.
Zohar
Z
Kerem
Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel.
Yoram
Y
Eyal
Institute of Plant Sciences, Agricultural Research Organization, P.O. Box 6, Bet-Dagan, 50250, Israel. vhmoshea@agri.gov.il.
Moshe A
MA
Flaishman
D002734:Chlorophyll / Q000378:metabolism*; D003001:Cloning, Molecular; D030681:Ficus / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D005638:Fruit / Q000254:growth & development / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D053858:Metabolic Networks and Pathways; D010312:Parthenogenesis; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054817:Pollination; D012098:Reproduction
D010940:Plant Proteins; D002734:Chlorophyll
Chlorophyll biosynthesis; Chlorophyll degradation genes; Ficus carica; Fruit development; Fruit pollination; Fruit ripening