Project description:Purpose: Gracilariopsis lemaneiformis is one of main economical species cultivated seaweed in China. The yield of G. lemaneiformis was positive related with its rhizoid branching number and length, whereas the regulation on branching and growth of G. lemaneiformis was unclear. IAA was well known to control morphogenesis and growth in land plants. This study aimed to evaluate the roles of IAA on the growth and branch formation of G. lemaneiformis rhizoids. Methods: Total RNA was extracted from G. lemaneiformis with branch and 2 cm of primary branch at 1 and 3 d after IAA treatment, respectively using the RNeasy Plant Mini Kit (Qiagen, Hilden, Germany). Three biological replicates are included for a treatment. RNA-seq were conducted by BGI, Shenzhen. Trinity (v2.0.6) was used to assemble the clean reads and Tgicl (v2.0.6) to perform clustering and eliminate redundant data in the assembled transcripts to obtain unique genes. Results: IAA could activate the pathways in ABCB auxin transporters, precursor biosynthesis of growth-related hormones and plant hormone signal transduction. IAA promoted the precursors synthesis of CTKs, GAs and BR and activated the ARFs involved in IAA signal transduction, and ARR-A and ARR-B involved in CTKs signal transduction, which further regulate the genes encoding cyclin-dependent kinases, cyclins, tubulin, and cell division cycle involved in cell division process. Meanwhile, carbon fixation, carbohydrate metabolism, energy metabolism, and amino acid biosynthesis and metabolism were also responsive to IAA, revealed that IAA induced to produce more energy and metabolic intermediates for cell growth.
