Comparative analysis of periderm suberin in stems and roots of Tetraena mongolica Maxim and Zygophyllum xanthoxylum (Bunge) Engl

Key message The chemical analysis and the expression patterns of related genes were determined to reveal and compare the adaptation mechanism of T. mongolica and Z. xanthoxylum to arid environments. Tetraena mongolica Maxim, the only member of the Tetraena genus in the Zygophyllaceae, is endemic to the northwest of China and is normally accompanied by another plant species in the same taxonomic family, Z. xanthoxylum (Bunge) Engl, and they play a key role in the ecology of the local environment. In order to survive in the local arid environment, many plants have developed a variety of adaptive mechanisms, including the formation of effective protective barrier, such as suberin in the stems and roots that can prevent plants from losing water and improve their adaptability to water-deficient environments. Previous studies have shown that Z. xanthoxylum had stronger drought tolerance than T. mongolica . Here, the water loss rates, the chemical composition of suberin and associated fatty acids in the periderms of stems and roots from T. mongolica and Z. xanthoxylum were determined. The expression level of genes related to suberin and associated fatty acid metabolism of the two species were also analyzed through transcriptome sequencing. The results showed that the stem and root periderms of these two species had similar chemical composition of suberin and fatty acids; however, much higher amount of suberin monomers and fatty acids were found in T. mongolica . Accordingly, transcriptome sequencing showed that more of the differentially expressed genes (DEGs) associated with suberin and associated fatty acid biosynthesis were up-regulated in the stem periderms of T. mongolica ; however, minority of DEGs were up-regulated in root periderms of T. mongolica , compared with Z. xanthoxylum . This study lays an important foundation for revealing the adaptation mechanism of T. mongolica and Z. xanthoxylum to arid environments and for comparing the adaptability differences of these two species.