Gene engineering on the control of ethylene biosynthesis in apple fruit.

An allele of the ACC synthase gene （Md-ACS1）the transcript and translated product of which have been identified in ripening apples，was isolated from a genomic library of the apple cultivar 'Golden Delicious'. the predicted codingregion of this allele (ACS1-2) showed that 7 nucleotide substitutions in the corresponding region ofACS1-1 resulted in just one amino acid transition. A 162 bp sequence characterized as A shortinterspersed repetitive element (SINE) retrotransposon was inserted in the 5' flanking region ofACS1-2 corresponding to position -781 in ACS1-1. The XhoI site located near The 3' end of Thepredicted coding region of ACS1-2 was absent from the reverse transcriptase-polymerase chainreaction (RT-PCR) productrevealing that exclusive transcription from ACS1-1 occurs during ripening of ‘Golden Delicious’fruit. DNA gel blot and PCR analyses of genomic DNAS showed clearly that apple cultivars were eitherheterozygous for ACS1-1 and ACS1-2 or homozygous for each type. .RNA gel blot analysis of the ACS1-2 homozygous 'Fuji' apple，产品little ethylene and has a long storage lifedemonstrated that the level of transcription from ACS 12 during the ripening stage was verylow.Apple species可以分类三个组，即是heterozygous或homozygous for theACS1-1和ACS1-2 alleles. We measured the internal ethylene concentration (IEC) in climactericfruit of 35 apple cultivars with genotype. Eleven ACS1-2 homozygous cultivars exhibitedmuch lower IECs than cultivars homozygous or heterozygous for ACS1-1. Furthermore，F - 2d2 ACS1-2 homozygous progeny derived from crosses between heterozygous cultivars fruitedwith a very low IEC.这些报告在前数据指示absence of data indicating absence of accordtranscription from ACS1-2 in a heterozygous cultivar.自ACS1 mRNA in the low level of ACS1climacteric fruit was observed in several ACS1-2 homozygous cultivars，我们包含在某些cultivars的低级ethylene production in some cultivars is caused by the mutatedallele of ACS1, which is the main gene responsible for ethylene production during ripening. Less

An allele of the ACC synthase gene (Md-ACS1), the transcript and translated product of which have been identified in ripening apples, was isolated from a genomic library of the apple cultivar 'Golden Delicious'. The predicted coding region of this allele (ACS1-2) showed that 7 nucleotide substitutions in the corresponding region of ACS1-1 resulted in just one amino acid transition. A 162 bp sequence characterized as a short interspersed repetitive element (SINE) retrotransposon was inserted in the 5' flanking region of ACS1-2 corresponding to position -781 in ACS1-1. The XhoI site located near the 3' end of the predicted coding region of ACS1-2 was absent from the reverse transcriptase-polymerase chain reaction (RT-PCR) product, revealing that exclusive transcription from ACS1-1 occurs during ripening of 'Golden Delicious' fruit. DNA gel blot and PCR analyses of genomic DNAS showed clearly that apple cultivars were either heterozygous for ACS1-1 and ACS1-2 or homozygous for each type. … More RNA gel blot analysis of the ACS1-2 homozygous 'Fuji' apple, which produces little ethylene and has a long storage life, demonstrated that the level of transcription from ACS 1 2 during the ripening stage was very low.Apple species can be classified into three groups that are heterozygous or homozygous for the ACS1-1 and ACS1-2 alleles. We measured the internal ethylene concentration (IEC) in climacteric fruit of 35 apple cultivars with respect to genotype. Eleven ACS1-2 homozygous cultivars exhibited much lower IECs than cultivars homozygous or heterozygous for ACS1-1. Furthermore, FィイD21ィエD2 ACS1-2 homozygous progeny derived from crosses between heterozygous cultivars fruited with a very low IEC. These results are in accord with previous data indicating absence of transcription from ACS1-2 in a heterozygous cultivar. Since the low level of ACS1 mRNA in climacteric fruit was observed in several ACS1-2 homozygous cultivars, we conclude that the low level of ethylene production in some cultivars is caused by the mutated allele of ACS1, which is the main gene responsible for ethylene production during ripening. Less