Two Oleosins Expressed in the Mesocarp of Native Mexican Avocado, Key Genes in the Oil Content

Integrative Analysis of Oleosin Genes Provides Insights into Lineage-Specific Family Evolution in Brassicales

“…To gain insight into lineage-specific family evolution in Brassicales, recently available chromosome (Chr)-level genome assemblies of A. trichopoda (a single living representative within the sister lineage Amborellales to all other flowering plants) [24], avocado (Persea americana, a Laurales member of an early-branching lineage of angiosperms that includes one M oleosin) [25], and A. coerulea (a Ranunculales member of the basal-most eudicot clade) [26] were first employed to identify oleosin family genes, resulting in five, three, and five members, respectively (Table 1). Five members identified in A. trichopoda and A. coerulea are consistent with what is found in previous assemblies [8], whereas only two avocado oleosin genes (i.e., PaOLE2 and -3) have been reported by previous studies [4,27]. Moreover, an allele for PaOLE2 that was discarded for further analyses in this study was also identified from tig00003364, and their coding sequences (CDS) were shown to exhibit 98.8% sequence identity, including only five single nucleotide polymorphisms (SNPs).…”

“…As shown in Figure 1 A, they were clustered into six clades, five of which were previously defined as U, SL, SH, T, and M [ 4 , 8 ]. Whereas Clade T is restricted to Arabidopsis ( Arabidopsis thaliana ), Clade M, which was first described in the Lauraceae family [ 4 , 27 ], was unexpectedly found in all species examined in this study. The presence of Clade M in A. trichopoda (i.e., AtrOLE2 ) supports its early origin before the radiation of angiosperms.…”

“…It is worth noting that, besides At - S3 and At - S5 , both At - T1 and At - T8 were also characterized as syntelogs of CpOLE3 , which provides direct evidence for the origin of Clade T from Clade SL. Additionally, PaOLE3 , a well-identified M member [ 4 , 27 ], still has syntelogs in A. trichopoda (i.e., AtrOLE2 ) and A. coerulea (i.e., AcOLE2 ) ( Figure 4 A), whereas AcOLE2 still has syntelogs in poplar ( Populus trichocarpa ) (i.e., PtOLE2a /- 2b ) and cassava (i.e., MeOLE2 ) ( Figure 4 B).…”