Physiological parameters and differential expression analysis of N-phenyl-N′-[6-(2-chlorobenzothiazol)-yl] urea-induced callus of Eucalyptus urophylla × Eucalyptus grandis

Abstract

In this study, we analyzed differences in the enzyme activities and transcriptomes of embryogenic and non-embryogenic calli to gain insights for improving the success of tissue culture-based breeding. A total of 2,856 differentially expressed genes (DEGs; 1,632 up-regulated and 1,224 down-regulated) were identified based on RNA sequencing and verified by reverse transcription quantitative polymerase chain reaction. Gene set enrichment analysis revealed that many of the up-regulated DEGs in embryogenic callus were enriched in the photosynthesis processes. Furthermore, the enzyme activity, hormone content, and cytokinin oxidase/dehydrogenase (CKX) gene expression analyses were found to be consistent with the transcriptome results. Cytokinin biosynthesis in N-phenyl-N′-[6-(2-chlorobenzothiazol)-yl] urea (PBU)-induced embryogenic callus increased owing to CKX repression. Measurement of endogenous hormones by high-performance liquid chromatography revealed that, compared with non-embryogenic callus, in embryogenic callus, the indole-3-acetic acid, abscisic acid and trans-zeatin riboside content had significantly higher values of 129.7, 127.8 and 78.9 ng/g, respectively. Collectively, the findings of this study will provide a foundation for elucidating the molecular mechanisms underlying embryogenic callus differentiation and can potentially contribute to developing procedures aimed at enhancing the success of callus-based plant regeneration.

Protuberances are organized distinct regions of long-term callus: histological and transcriptomic analyses in kiwifruit

“…Transcriptome profiling is a useful tool for distinguishing structures with morphological similarity and to confirm their different nature (Chen et al 2019 ). Additionally, the gene expression during callus induction and proliferation, as well as the regeneration processes from callus, and then de novo shoot bud regeneration, has received more and more attention from researchers (Nakano et al 2018 ; Fu et al 2019 ; Gao et al 2019 ; Ikeuchi et al 2019 and references therein; Lee and Huang 2019 , Ouyang et al 2020 ).…”

E. urophylla × E. grandis high-quality genome and comparative genomics provide insights on evolution and diversification of eucalyptus

“…Eucalyptus, belonging to the Myrtaceae family, grows rapidly, is widely cultivated worldwide (over 20 million hm 2 ) [ 1 ], and has a high economic value because of its wide range of uses. Introduced to China more than 120 years ago, eucalyptus provides an annual wood output of more than 40 million m 3 and more than 50% of China’s pulping materials [ 2 ].…”

Efficient genetic transformation method for Eucalyptus genome editing

“…The common method for screening resistance buds using antibiotics is extremely inefficient, and its accuracy is low. Currently, only a few studies have focused on finding an efficient genetic transformation system for Eucalyptus [4,8,9]. Successful A. tumefaciens-mediated transformation in most plants depends on the effectiveness of appropriate selection conditions.…”