Full-Length Transcriptome Analysis of the ABCB, PIN/PIN-LIKES, and AUX/LAX Families Involved in Somatic Embryogenesis of Lilium pumilum DC. Fisch.

Abstract

Plant cell totipotency is one of the 25 major topics in current scientific research, and somatic embryos are good experimental material for studying cell totipotency. Polar auxin transport plays an important regulatory role in somatic embryogenesis (SE). However, little is known about the auxin transport genes and their regulatory mechanisms in Lilium SE. In this study, we applied single-molecule real-time (SMRT) sequencing to Lilium pumilum DC. Fisch. for the first time and obtained a total of 119,649 transcripts, of which 14 encoded auxin transport genes. Correlation analyses between somatic embryo induction and gene expression under different treatments revealed that auxin transport genes, especially ATP-binding cassette (ABC) transporter B family member 21 (ABCB21) and PIN-FORMED (PIN) LIKES 7 (PILS7), may be key players in SE, and the necessary duration of picloram (PIC) treatment to induce SE is as short as 3 days. Our research provides valuable genetic information on Lilium pumilum, elucidating the candidate auxin transport genes involved in SE and their influencing factors. This study lays a foundation for elucidating the regulatory mechanism of auxin transport in SE.

Improvement of a Genetic Transformation System and Preliminary Study on the Function of LpABCB21 and LpPILS7 Based on Somatic Embryogenesis in Lilium pumilum DC. Fisch

“…This phenomenon may be explained by very high rate of auxin transport [ 6 ]; hence, the process of exogenous hormone transport into the cells, which is probably determined by LpABCB21 , is not affected. Our previous study demonstrated that LpPILS7 expression level is increased in the light culture, and somatic embryo induction efficiency in the light culture is better than that in the dark culture [ 40 ]. This experiment confirms that LpPILS7 can promote L. pumilum SE.…”

“…The genetic transformation method was performed as described previously [ 40 ]. In brief, EC were transferred to somatic embryo induction medium for proliferation and subcultured every 30 days until genetic transformation was performed.…”

“…Specific primers for identification of overexpression in plants were designed based on the 35S promoter sequence (35S-F), the inserted DNA fragments (B21-R and S7-R), and the NPT II sequence ( NTP II-F and NTP II-R). The expression levels in the overexpression plants were detected according to the previously described method [ 40 ]. Specific primers for identification of knockout plants were designed based on the OsU3 and TaU3 promoter (OsU3p and TaU3p) [ 56 ].…”

“…At present, the regulatory role of auxin transport in somatic embryogenesis (SE) remains unclear. Our previous results demonstrated that the expression levels of LpABCB21 and LpPILS7 auxin transporters are significantly up-regulated in SE and may play an important regulatory role in L. pumilum SE [ 40 ]. Moreover, the genetic transformation system of L. pumilum developed previously by our team [ 39 ] is improved by optimization of the pH of RC (re-suspension solution and co-culture medium), and the germination conditions of resistant calli.…”

SMRT and Illumina RNA-Seq Identifies Potential Candidate Genes Related to the Double Flower Phenotype and Unveils SsAP2 as a Key Regulator of the Double-Flower Trait in Sagittaria sagittifolia

“…It was reported that the expression of AUX/IAA transcriptional regulatory genes related to IAA was affected by AUX biosynthesis and signal transduction genes. Auxin and response factors act as transcriptional factors to regulate the expression of auxin response genes by binding to specific sequences of auxin response elements, and they play a role in flower development through transcriptional activation or inhibition [38,39].…”