Comparative profiling of miRNA expression in developing seeds of high linoleic and high oleic safflower (Carthamus tinctorius L.) plants

Abstract

Vegetable oils high in oleic acid are considered to be advantageous because of their better nutritional value and potential industrial applications. The oleic acid content in the classic safflower oil is normally 10–15% while a natural mutant (ol) accumulates elevated oleic acid up to 70% in seed oil. As a part of our investigation into the molecular features of the high oleic (HO) trait in safflower we have profiled the microRNA (miRNA) populations in developing safflower seeds expressing the ol allele in comparison to the wild type high linoleic (HL) safflower using deep sequencing technology. The small RNA populations of the mid-maturity developing embryos of homozygous ol HO and wild type HL safflower had a very similar size distribution pattern, however, only ~16.5% of the unique small RNAs were overlapping in these two genotypes. From these two small RNA populations we have found 55 known miRNAs and identified two candidate novel miRNA families to be likely unique to the developing safflower seeds. Target genes with conserved as well as novel functions were predicted for the conserved miRNAs. We have also identified 13 miRNAs differentially expressed between the HO and HL safflower genotypes. The results may lay a foundation for unraveling the miRNA-mediated molecular processes that regulate oleic acid accumulation in the HO safflower mutant and developmental processes in safflower embryos in general.

Salt and drought stresses in safflower: a review

“…Furthermore, Cao et al (2013) investigated the molecular basis of the high oleic (HO) trait in safflower and compared the miRNA populations in developing safflower seeds expressing the olallele in comparison to the wild-type high linoleic (HL). They detected 55 known miRNAs and identified two novel miRNA families of developing safflower seeds.…”

The pivotal role of small non-coding RNAs in the regulation of seed development

“…A list of 13 miRNAs differentially expressed between mid-maturity seeds from two genotypes of the ancient oilseed crop safflower (Carthamus tinctorius L.), with contrasting fatty acid profiles, delivered some potential candidates to pursuit functional studies. Three of these miRNA candidates, highly expressed by the genotype producing seed oil with considerably higher oleic acid content, namely miR395, miR397 and miR5026 (Cao et al 2013) seemed particularly relevant. In canola (Brassica napus), sRNAs involvement in lipid metabolism has been covered from early embryogenesis to maturation Wang et al 2016), revealing differences between high-and low-oilcontent siliques right at early embryogenesis.…”

“…Recent sRNA research related to oilseed content provides further examples of how specific miRNA-target interactions can be potentially used in breeding to improve seed nutritional value (Cao et al 2013;Zhao et al 2012;Wang et al 2016) or biodiesel production (Cao et al 2013;Galli et al 2014). Contrasting oilseed content genotypes appear to share a small percentage of unique sRNA sequences (Cao et al 2013), and available studies suggest some miRNAs are possibly associated with the different metabolic profiles presented by high-and low-oil-content seeds.…”

“…Contrasting oilseed content genotypes appear to share a small percentage of unique sRNA sequences (Cao et al 2013), and available studies suggest some miRNAs are possibly associated with the different metabolic profiles presented by high-and low-oil-content seeds. A list of 13 miRNAs differentially expressed between mid-maturity seeds from two genotypes of the ancient oilseed crop safflower (Carthamus tinctorius L.), with contrasting fatty acid profiles, delivered some potential candidates to pursuit functional studies.…”

Computational identification of conserved microRNAs and their targets from expression sequence tags of blueberry (Vaccinium corybosum)

“…48 miR5021 was also reported in a few plant species such as peach, ginseng, sunflower, radish, longan, Jatropha curcas, moth orchid, Brassica oleracea, and Arabidopsis. 24,26,[49][50][51][52][53][54] It was indicated that miR5021 families may be involved in the regulation of lipid metabolism and responses to stress, and MYB proteins and SPL3 transcription factor may be the target of miR5021. 26 Although miR156-3p, miR1522, miR5658, miR5783, and miR5998 were also identified in other species, their functional roles remain unknown as yet.…”