Dataset Information

Sequence analysis of ripening-related cytochrome P-450 cDNAs from avocado fruit.

ABSTRACT: The ripening of avocado fruit is associated with the expression of a number of mRNAs concomitant with overt changes in texture and flavor. Two overlapping cDNAs for a mRNA that accumulates during ripening were identified. Sequence analysis of these two cDNAs revealed a polypeptide of 471 amino acids with characteristics of a typical P-450: an N-terminal hydrophobic membrane anchor, a conserved heme-binding domain in the C-terminal region, and patches of similarity to various P-450 family members. Further evidence that this polypeptide represents a cytochrome P-450 oxidase comes from the recent isolation and characterization of a cytochrome P-450 from ripe avocado mesocarp [O'Keefe, D. P. & Leto, K. J. (1989) Plant Physiol. 89, 1141-1149]. The N terminus of the predicted polypeptide in the cDNAs is identical to the N terminus of the purified avocado P-450. Gel blot analysis of RNA from fruit at various stages of ripening showed the accumulation of an 1800-nucleotide P-450 mRNA that hybridized to the P-450 cDNA. The P-450 protein predicted by the avocado cDNA sequence shares less than 40% positional identity with any known P-450 gene family. We propose therefore that it be placed in a separate family, P450LXXI, and that the corresponding gene from avocado be named cyp71A1.

SUBMITTER: Bozak KR

PROVIDER: S-EPMC54012 | biostudies-other | 1990 May

REPOSITORIES: biostudies-other

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Sequence analysis of ripening-related cytochrome P-450 cDNAs from avocado fruit.

Bozak K R KR Yu H H Sirevåg R R Christoffersen R E RE

Proceedings of the National Academy of Sciences of the United States of America 19900501 10

The ripening of avocado fruit is associated with the expression of a number of mRNAs concomitant with overt changes in texture and flavor. Two overlapping cDNAs for a mRNA that accumulates during ripening were identified. Sequence analysis of these two cDNAs revealed a polypeptide of 471 amino acids with characteristics of a typical P-450: an N-terminal hydrophobic membrane anchor, a conserved heme-binding domain in the C-terminal region, and patches of similarity to various P-450 family members ...[more]

PMID: 1692626

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Project description:BackgroundAvocado fruit contains aliphatic acetogenins (oft-acetylated, odd-chain fatty alcohols) with promising bioactivities for both medical and food industries. However, we have scarce knowledge about their metabolism. The present work aimed to study changes in acetogenin profiles from mesocarp, lipid-containing idioblasts, and seeds from 'Hass' cultivar during fruit development, germination, and three harvesting years. An untargeted LC-MS based lipidomic analysis was also conducted to profile the lipidome of avocado fruit in each tissue.ResultsThe targeted analysis showed that acetogenin profiles and contents remained unchanged in avocado mesocarp during maturation and postharvest ripening, germination, and different harvesting years. However, a shift in the acetogenin profile distribution, accompanied with a sharp increase in concentration, was observed in seed during early maturation. Untargeted lipidomics showed that this shift was accompanied with remodeling of glycerolipids: TAGs and DAGs decreased during fruit growing in seed. Remarkably, the majority of the lipidome in mature seed was composed by acetogenins; we suggest that this tissue is able to synthesize them independently from mesocarp. On the other hand, lipid-containing idioblasts accumulated almost the entire acetogenin pool measured in the whole mesocarp, while only having 4% of the total fatty acids. The lipidome of this cell type changed the most when the fruit was ripening after harvesting, TAGs decreased while odd-chain DAGs increased. Notably, idioblast lipidome was more diverse than that from mesocarp.ConclusionsEvidence shown here suggests that idioblasts are the main site of acetogenin biosynthesis in avocado mesocarp. This work unveiled the prevalence of aliphatic acetogenins in the avocado fruit lipidome and evidenced TAGs as initial donors of the acetogenin backbones in its biosynthesis. It also sets evidence for acetogenins being included in future works aimed at characterizing the avocado seed, as they are a main component of their lipidome.

Dataset Information

Sequence analysis of ripening-related cytochrome P-450 cDNAs from avocado fruit.

Publications

Sequence analysis of ripening-related cytochrome P-450 cDNAs from avocado fruit.

Similar Datasets

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