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Characterization of FAE1 in the zero erucic acid germplasm of Brassica rapa L.

Yan G, Li D, Cai M, Gao G, Chen B, Xu K, Li J, Li F, Wang N, Qiao J, Li H, Zhang T, Wu X - Breed. Sci. (2015)

Bottom Line: Here, we isolated zero erucic acid lines from 1981 Chinese landraces of B. rapa and found that the formation of LEA is not attributable to variations in FAE1 coding sequences, as reported for B. napus, but may be attributable to the decrease in FAE1 expression.This study isolated an LEA B. rapa resource that can be exploited in Brassica cultivation.The promoter variations might modify the expression level of FAE1, and the results shed light on novel regulation mechanisms for erucic acid synthesis.

View Article: PubMed Central - PubMed

Affiliation: Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture , Wuhan 430062 , P. R. China.

ABSTRACT
The modification of erucic acid content in seeds is one of the major goals for quality breeding in oil-yielding Brassica species. However, few low erucic acid (LEA) resources are available, and novel LEA genetic resources are being sought. Fatty acid elongase 1 (FAE1) is the key gene that controls erucic acid synthesis. However, the mechanism for erucic acid synthesis in B. rapa lacks systematic study. Here, we isolated zero erucic acid lines from 1981 Chinese landraces of B. rapa and found that the formation of LEA is not attributable to variations in FAE1 coding sequences, as reported for B. napus, but may be attributable to the decrease in FAE1 expression. Moreover, the FAE1 promoter sequences of LEA and high erucic acid materials shared 95% similarity. Twenty-eight bases deletions (containing a 24-base AT-rich region) were identified approximately 1300 bp upstream from the FAE1 start codon in the LEA accessions. The genotype with the deletions co-segregated with the LEA trait in the segregating population. This study isolated an LEA B. rapa resource that can be exploited in Brassica cultivation. The promoter variations might modify the expression level of FAE1, and the results shed light on novel regulation mechanisms for erucic acid synthesis.

No MeSH data available.


The amplicons amplified by the primer pair pM120F and pM468R in the F2 population of Sanjiecaizi (e/e) × Nanhualinggongdacaizi (E/E). The amplicon contained one insertion in addition to the 28 deletions (as shown in Fig. 4). Therefore, the fragments amplified from the e/e genotype were 27 bases shorter than those from the E/E genotype, which was confirmed using sequencing. (a) M, DNA ladder; S, Sanjiecaizi (e/e), zero erucic line, 317 bp; F1 plants with a erucic acid content of 30.36 ± 5.02%, Sanjiecaizi × Nanhualinggongdacaizi, 344 bp and 317 bp; N, Nanhualinggongdacaizi (E/E), high erucic line, 344 bp; 1 to 5, F2 plants with a low erucic acid content (average 0.75% ± 1.32%); 6 to 10, F2 plants with a erucic acid content of 35.12 ± 7.94%; 11 to 15, F2 plants with a high erucic acid content (43.64% ± 10.60%). (b) Box plot showing the erucic acid content range and median for the three genotypes. e/e: homozygous genotype resembling the zero erucic acid parent Sanjiecaizi. E/e: heterozygous genotype containing both alleles of the two parents. E/E: homozygous genotype resembling HEA Nanhualinggongdacaizi. Note: Capital letters indicate significant differences at the 0.01 level.
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f5-65_257: The amplicons amplified by the primer pair pM120F and pM468R in the F2 population of Sanjiecaizi (e/e) × Nanhualinggongdacaizi (E/E). The amplicon contained one insertion in addition to the 28 deletions (as shown in Fig. 4). Therefore, the fragments amplified from the e/e genotype were 27 bases shorter than those from the E/E genotype, which was confirmed using sequencing. (a) M, DNA ladder; S, Sanjiecaizi (e/e), zero erucic line, 317 bp; F1 plants with a erucic acid content of 30.36 ± 5.02%, Sanjiecaizi × Nanhualinggongdacaizi, 344 bp and 317 bp; N, Nanhualinggongdacaizi (E/E), high erucic line, 344 bp; 1 to 5, F2 plants with a low erucic acid content (average 0.75% ± 1.32%); 6 to 10, F2 plants with a erucic acid content of 35.12 ± 7.94%; 11 to 15, F2 plants with a high erucic acid content (43.64% ± 10.60%). (b) Box plot showing the erucic acid content range and median for the three genotypes. e/e: homozygous genotype resembling the zero erucic acid parent Sanjiecaizi. E/e: heterozygous genotype containing both alleles of the two parents. E/E: homozygous genotype resembling HEA Nanhualinggongdacaizi. Note: Capital letters indicate significant differences at the 0.01 level.

Mentions: The primer pair pM120F/pM468R was specifically designed for the region carrying the 28 bases deletions in the promoter of FAE1 to reveal the relationship between the phenotypes and the deletions (as shown in Fig. 4). The amplicons could be accurately scored by size difference on 2.5% agarose gels. The primers produced a 317-bp fragment in the zero erucic acid Sanjiecaizi, whereas a 344-bp fragment was produced in the HEA Nanhualinggongdacaizi; 317-bp and 344-bp fragments were produced in the heterozygous F1 individuals (with an erucic acid content of 30.36 ± 5.02%), as predicted (Fig. 5a). In 118 F2 plants from the Sanjiecaizi (e/e) × Nanhualinggongdacaizi (E/E) cross, 30 plants with amplicons resembling the zero erucic acid parent Sanjiecaizi were LEA lines (0.75% ± 1.32%); 38 plants with amplicons resembling the HEA parent Nanhualinggongdacaizi had an erucic acid content of 43.64 ± 10.60%, and 50 heterozygous individuals had an erucic acid content of 35.12 ± 7.94% (Fig. 5a, 5b). The segregation ratio of the three genotypes in the F2 population agreed perfectly with the expected ratio of 1 : 2 : 1 (χ2 = 3.83, P = 0.147). The result showed that all LEA plants were e/e homozygous and the erucic acid content of the e/e genotype was highly significantly different from that of the E/E and E/e genotypes (p < 0.01) (Fig. 5b). Therefore, the homozygosity with the 28 bases deletions co-segregated with the LEA phenotypes.


Characterization of FAE1 in the zero erucic acid germplasm of Brassica rapa L.

Yan G, Li D, Cai M, Gao G, Chen B, Xu K, Li J, Li F, Wang N, Qiao J, Li H, Zhang T, Wu X - Breed. Sci. (2015)

The amplicons amplified by the primer pair pM120F and pM468R in the F2 population of Sanjiecaizi (e/e) × Nanhualinggongdacaizi (E/E). The amplicon contained one insertion in addition to the 28 deletions (as shown in Fig. 4). Therefore, the fragments amplified from the e/e genotype were 27 bases shorter than those from the E/E genotype, which was confirmed using sequencing. (a) M, DNA ladder; S, Sanjiecaizi (e/e), zero erucic line, 317 bp; F1 plants with a erucic acid content of 30.36 ± 5.02%, Sanjiecaizi × Nanhualinggongdacaizi, 344 bp and 317 bp; N, Nanhualinggongdacaizi (E/E), high erucic line, 344 bp; 1 to 5, F2 plants with a low erucic acid content (average 0.75% ± 1.32%); 6 to 10, F2 plants with a erucic acid content of 35.12 ± 7.94%; 11 to 15, F2 plants with a high erucic acid content (43.64% ± 10.60%). (b) Box plot showing the erucic acid content range and median for the three genotypes. e/e: homozygous genotype resembling the zero erucic acid parent Sanjiecaizi. E/e: heterozygous genotype containing both alleles of the two parents. E/E: homozygous genotype resembling HEA Nanhualinggongdacaizi. Note: Capital letters indicate significant differences at the 0.01 level.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4482176&req=5

f5-65_257: The amplicons amplified by the primer pair pM120F and pM468R in the F2 population of Sanjiecaizi (e/e) × Nanhualinggongdacaizi (E/E). The amplicon contained one insertion in addition to the 28 deletions (as shown in Fig. 4). Therefore, the fragments amplified from the e/e genotype were 27 bases shorter than those from the E/E genotype, which was confirmed using sequencing. (a) M, DNA ladder; S, Sanjiecaizi (e/e), zero erucic line, 317 bp; F1 plants with a erucic acid content of 30.36 ± 5.02%, Sanjiecaizi × Nanhualinggongdacaizi, 344 bp and 317 bp; N, Nanhualinggongdacaizi (E/E), high erucic line, 344 bp; 1 to 5, F2 plants with a low erucic acid content (average 0.75% ± 1.32%); 6 to 10, F2 plants with a erucic acid content of 35.12 ± 7.94%; 11 to 15, F2 plants with a high erucic acid content (43.64% ± 10.60%). (b) Box plot showing the erucic acid content range and median for the three genotypes. e/e: homozygous genotype resembling the zero erucic acid parent Sanjiecaizi. E/e: heterozygous genotype containing both alleles of the two parents. E/E: homozygous genotype resembling HEA Nanhualinggongdacaizi. Note: Capital letters indicate significant differences at the 0.01 level.
Mentions: The primer pair pM120F/pM468R was specifically designed for the region carrying the 28 bases deletions in the promoter of FAE1 to reveal the relationship between the phenotypes and the deletions (as shown in Fig. 4). The amplicons could be accurately scored by size difference on 2.5% agarose gels. The primers produced a 317-bp fragment in the zero erucic acid Sanjiecaizi, whereas a 344-bp fragment was produced in the HEA Nanhualinggongdacaizi; 317-bp and 344-bp fragments were produced in the heterozygous F1 individuals (with an erucic acid content of 30.36 ± 5.02%), as predicted (Fig. 5a). In 118 F2 plants from the Sanjiecaizi (e/e) × Nanhualinggongdacaizi (E/E) cross, 30 plants with amplicons resembling the zero erucic acid parent Sanjiecaizi were LEA lines (0.75% ± 1.32%); 38 plants with amplicons resembling the HEA parent Nanhualinggongdacaizi had an erucic acid content of 43.64 ± 10.60%, and 50 heterozygous individuals had an erucic acid content of 35.12 ± 7.94% (Fig. 5a, 5b). The segregation ratio of the three genotypes in the F2 population agreed perfectly with the expected ratio of 1 : 2 : 1 (χ2 = 3.83, P = 0.147). The result showed that all LEA plants were e/e homozygous and the erucic acid content of the e/e genotype was highly significantly different from that of the E/E and E/e genotypes (p < 0.01) (Fig. 5b). Therefore, the homozygosity with the 28 bases deletions co-segregated with the LEA phenotypes.

Bottom Line: Here, we isolated zero erucic acid lines from 1981 Chinese landraces of B. rapa and found that the formation of LEA is not attributable to variations in FAE1 coding sequences, as reported for B. napus, but may be attributable to the decrease in FAE1 expression.This study isolated an LEA B. rapa resource that can be exploited in Brassica cultivation.The promoter variations might modify the expression level of FAE1, and the results shed light on novel regulation mechanisms for erucic acid synthesis.

View Article: PubMed Central - PubMed

Affiliation: Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture , Wuhan 430062 , P. R. China.

ABSTRACT
The modification of erucic acid content in seeds is one of the major goals for quality breeding in oil-yielding Brassica species. However, few low erucic acid (LEA) resources are available, and novel LEA genetic resources are being sought. Fatty acid elongase 1 (FAE1) is the key gene that controls erucic acid synthesis. However, the mechanism for erucic acid synthesis in B. rapa lacks systematic study. Here, we isolated zero erucic acid lines from 1981 Chinese landraces of B. rapa and found that the formation of LEA is not attributable to variations in FAE1 coding sequences, as reported for B. napus, but may be attributable to the decrease in FAE1 expression. Moreover, the FAE1 promoter sequences of LEA and high erucic acid materials shared 95% similarity. Twenty-eight bases deletions (containing a 24-base AT-rich region) were identified approximately 1300 bp upstream from the FAE1 start codon in the LEA accessions. The genotype with the deletions co-segregated with the LEA trait in the segregating population. This study isolated an LEA B. rapa resource that can be exploited in Brassica cultivation. The promoter variations might modify the expression level of FAE1, and the results shed light on novel regulation mechanisms for erucic acid synthesis.

No MeSH data available.