Differences in cold tolerance and expression of two fatty acid desaturase genes in the leaves between fingered citron and its dwarf mutant

Abstract

Fingered citron (Citrus medica L. var. sarcodactylis Swingle), a precious fruit ornamental plant, is sensitive to low temperature. Cold tolerance, evaluated by semi-lethal temperature, was lower in wild-type 'Qingpi' than in its mutant 'Aihua' trees obtained by c-radiation. The full-length cDNAs of two genes encoding fatty acid desaturases involved in unsaturated fatty acid biosynthesis were isolated from the fingered citron leaves. The Cms-FAD2 open reading frame (ORF) had 1,152 bp and was uninterrupted, encoding a polypeptide of 384 amino acids that showing 82% homology with the microsomal x-6 desaturase CiFAD2 in Davidia involucrate. The CmsFAD8 ORF contained 1,373 bp and 7 introns, encoding a polypeptide of 458 amino acids showing 76% homology with the plastidial x-3 desaturase BpFAD8 in Betula pendula. CmsFAD2 was expressed highly in leaves but low in roots and flowers, while CmsFAD8 was obviously expressed in three tissues. Compared with control group (28°C), the expression of CmsFAD2 and CmsFAD8 in leaves of two genotypes was significantly induced at 6°C. The increase of CmsFAD2 and CmsFAD8 was earlier and larger in coldtolerant 'Aihua' than in cold-sensitive 'Qingpi'. The linolenic acid content increased significantly in leaves of mutant 'Aihua' plants exposed to low temperature of 6°C. The results showed that a positive relationship between CmsFAD expression and genotype tolerance to cold may exist.

Chilling temperature remodels phospholipidome of Zea mays seeds during imbibition

“… 52 demonstrated that cold acclimation of olive drupes relied on FAD post-transcriptional regulation. Conversely other studies demonstrated that transcription of ω-6 desaturase was up-regulated by cold in cotton 53 , citrus 54 and cucumber 55 . In contrast, cold induced a rapid and transient expression of the plastidial desaturase fad6 in embryos of the tolerant hybrid only (Fig.…”

Cloning, Characterization, and Expression Analysis of Three FAD8 Genes Encoding a Fatty Acid Desaturase from Seeds of Paeonia ostii

“…sarcodactylis. Swingle showed that the expression level of the two genes correlated with the genotypes of the two plants [ 25 , 26 ]. In Arabidopsis , two types of omega-3 FADs ( FAD3 located in the ER and FAD7 / 8 located in the chloroplast) catalyze the formation of TA [ 7 , 26 , 27 ].…”

Fingered Citron—A Fragrant Ornamental Fruit Crop for Florida

“…However, fingered citron is very cold-sensitive and cannot tolerate frost, so it can only be grown outdoors in south Florida or in protected locations in central and north Florida. At temperatures below 45°F, fingered citron leaves wilt, photosynthetic rates decrease, and in severe cases, the tree dies (Guo et al 2009;Yang et al 2012). In areas with frost, trees can be transplanted to big containers and overwintered indoors with sufficient sunlight.…”

“…In areas with frost, trees can be transplanted to big containers and overwintered indoors with sufficient sunlight. Plant flowering and fruiting can also stagnate if undergoing cold stress (Yang et al 2012). Fruit matures and is ready to harvest from November to January, but eventually some fruits may appear year-round.…”

“…Fingered citron has long been used for ornamental and religious purposes in China and Japan due to its shape (Lim 2012). In China, fingered citron is grown in pots as an ornamental plant because it symbolizes happiness and longevity (Yang et al 2012). The segmented appearance of fingered citron makes this cultivar unique.…”