Articles
Ploidy identification, biological characteristics, and transcriptome analysis of diploid and autotetraploid Bauhinia purpurea
Article number
1455_21
Pages
167 – 176
Language
English
Abstract
Bauhinia purpurea L. has important ornamental, edible, and medicinal value.
Polyploid induction is an effective approach for trait improvement and new cultivar development.
To investigate the effects of polyploidy on horticultural traits and facilitate breeding, we generated putative polyploid plants via colchicine-mediated somatic induction and confirmed a tetraploid line (2n=4x=56) by flow cytometry combined with root-tip chromosome counts.
We then conducted a systematic comparison with the diploid at morphological, leaf anatomical, physiological, and transcriptomic levels.
Flow cytometry showed that nuclear DNA content in the tetraploid was approximately twice that of the diploid.
Relative to the diploid, the tetraploid exhibited significantly larger leaf area (+149.29%) and longer petiole (+13.97%), and significantly higher fresh and dry biomass (+188.62 and +183.05%). Guard cells were significantly enlarged, with length and width increased by +55.47 and +13.74%, respectively; whereas, stomatal density decreased significantly (-72.89%). Overall leaf thickness did not differ significantly; however, the upper epidermis, lower epidermis, and palisade tissue were thinner (-24.23, -7.89, -21.68%); while, the spongy mesophyll was thicker (+6.76%). Leaf vein thickness, as well as collenchyma, xylem, and parenchyma, increased significantly (+69.69, +143.61, +85.61, +332.94%). Physiologically, the net CO2 assimilation rate increased significantly (+52.79%); whereas, SPAD value, transpiration rate, and stomatal conductance showed no significant differences.
RNA-seq identified 296 DEGs (208 up- and 88 downregulated); GO terms were enriched for ADP binding and monooxygenase activity, and KEGG pathways were significantly enriched in biosynthesis of secondary metabolites and carbon metabolism. Several upregulated genes associated with growth, development, and metabolism were detected in the tetraploid, including CESA, AP2/ERF, CYP450, and MFS.
Polyploid induction is an effective approach for trait improvement and new cultivar development.
To investigate the effects of polyploidy on horticultural traits and facilitate breeding, we generated putative polyploid plants via colchicine-mediated somatic induction and confirmed a tetraploid line (2n=4x=56) by flow cytometry combined with root-tip chromosome counts.
We then conducted a systematic comparison with the diploid at morphological, leaf anatomical, physiological, and transcriptomic levels.
Flow cytometry showed that nuclear DNA content in the tetraploid was approximately twice that of the diploid.
Relative to the diploid, the tetraploid exhibited significantly larger leaf area (+149.29%) and longer petiole (+13.97%), and significantly higher fresh and dry biomass (+188.62 and +183.05%). Guard cells were significantly enlarged, with length and width increased by +55.47 and +13.74%, respectively; whereas, stomatal density decreased significantly (-72.89%). Overall leaf thickness did not differ significantly; however, the upper epidermis, lower epidermis, and palisade tissue were thinner (-24.23, -7.89, -21.68%); while, the spongy mesophyll was thicker (+6.76%). Leaf vein thickness, as well as collenchyma, xylem, and parenchyma, increased significantly (+69.69, +143.61, +85.61, +332.94%). Physiologically, the net CO2 assimilation rate increased significantly (+52.79%); whereas, SPAD value, transpiration rate, and stomatal conductance showed no significant differences.
RNA-seq identified 296 DEGs (208 up- and 88 downregulated); GO terms were enriched for ADP binding and monooxygenase activity, and KEGG pathways were significantly enriched in biosynthesis of secondary metabolites and carbon metabolism. Several upregulated genes associated with growth, development, and metabolism were detected in the tetraploid, including CESA, AP2/ERF, CYP450, and MFS.
Authors
Z.X. Li, G.Y. Lu, Y. Xiao, C.H. Hao, F.C. Wu
Keywords
root-tip chromosome counts, leaf, phenotype, RNA-seq, differentially expressed gene (DEG)
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