Abstract
BackgroundBreeding rubber tree seedling with growth heterosis is vital for natural rubber production. It is the prerequisites for effectively utilizing growth heterosis to elucidate its molecular mechanisms, but the molecular mechanisms remain poorly understood in rubber tree. To elucidate seedling growth heterosis, we conducted comparative transcriptomic analyses between the two hybrids and their parents.ResultsBy identifying and comparing differently expressed genes (DEGs), we found that the hybrids (BT 3410 and WC 11) show significantly differential expression profiles from their parents (PR 107 and RRIM 600). In BT 3410-parent triad, 1092 (49.95%) and 1094 (50.05%) DEGs indicated clear underdominance or overdominance, respectively. Whereas in WC 11-parent triad, most DEGs (78.2%, 721) showed low- or high-parent dominance; 160 (17.35%) exhibited expression patterns that are not statistically distinguishable from additivity, and 8 (0.87%) and 33 (3.58%) DEGs exhibited underdominance and overdominance, respectively. Furthermore, some biological processes are differentially regulated between two hybrids. Interestingly, the pathway in response to stimulus is significantly downregulated and metabolic pathways are more highly regulated in BT 3410.ConclusionsTaken together, the genotypes, transcriptomes and biological pathways (especially, carbohydrate metabolism) are highly divergent between two hybrids, which may be associated with growth heterosis and weakness. Analyzing gene action models in hybrid-parent triads, we propose that overdominance may play important roles on growth heterosis, whereas dominance on hybrid weakness in rubber tree seedlings. These findings bring new insights into our understanding of growth heterosis of rubber tree seedling.
Highlights
Breeding rubber tree seedling with growth heterosis is vital for natural rubber production
We found that underdominance and overdominance expression patterns, and differential expression of genes involved in the pathways of in response to stimulus, and carbohydrate metabolism may contribute to growth heterosis of rubber tree seedlings
Among 20 genes indicating gene action models, 7, 4, 2, 1, and 6 genes indicated High parent dominance (HPD), Low parent dominance (LPD), OD, AD, and UD gene action models in RY 7–33-97 and its parent triad, respectively (Fig. 4c). These results indicated that BT 3410, RY 7–33-97 and WC 11 show significantly different gene action models they are the offsprings of the same parents, which may contribute to growth heterosis and weakness of seedlings in these rubber tree hybrids, respectively
Summary
Breeding rubber tree seedling with growth heterosis is vital for natural rubber production. To elucidate seedling growth heterosis, we conducted comparative transcriptomic analyses between the two hybrids and their parents. Three main genetic models are proposed to explain heterosis [1, 4]. In contrast to dominance model, overdominance proposes that heterosis comes from favorable allelic interactions at heterozygous loci [6]. Epistasis coming from gene-by-gene interactions is a third genetic model to explain heterosis [7]. In contrast to its parents, a hybrid usually indicates expression levels of genes equal to the mid-parent (additivity, AD), the high or low parent (high or low parent dominance, HPD or LPD), above the high parent (overdominance, OD), or below the low parent (underdominance, UD)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
