Propagation of pineapple (Ananas comosus L.) embryogenic cell suspension is regulated by LEAFY COTYLEDON1 gene AcoLEC1–1

Abstract

Pineapple (Ananas comosus L.) is an important tropical fruit. Traditional breeding methods take about 15 years, but transgenic breeding using embryogenic cell suspension (ECS) can significantly shorten this cycle. Four different calli types were produced using the pineapple crown's middle stem part as an explant: water-like, solid, gemmiform, and crisp. The fastest multiplication was observed in suspension cultures obtained from the loose, crispy, granular, white, or yellow callus. The highest cell density in the liquid medium was achieved with MS+1.5 mg/L+4 mg/L6-BA+300 mg/L hormone combination. Inclusion of 11 mmol/L 2-morpholinoethanesulfonic acid (MES) stabilized the medium pH. The optimum sucrose concentration for pineapple propagation using ECS was 5 g/L. The expression of seven proteins in ECS in the medium containing 5 g/L sucrose was more than 5.0 times higher than in the medium containing 3 g/L. The expression of transcription factor NFYB/HAP3 (or LEAFY COTYLEDON1, LEC1) was the highest in the medium. The most prevalent AcoLEC1–1 transcripts were found in the embryogenic callus, and their patterns correlated well with ECS volume. AcoLEC1–1 played a key role in the process of sucrose-regulated ECS propagation.