Characterization and expression of the partial flowering locus t-2 gene in the shallot (Allium cepa var. Aggregatum) cultivar ‘Lokananta’

Abstract

Shallot (Allium cepa var. Aggregatum) is an economically important nutritive vegetable and medicinal plant. Given their low seed production, shallots are vegetatively propagated by using bulb material. Flowering is essential for transferring important traits, such as resistance to Fusarium oxysporum and tolerance to salinity. However, the flowering abilities and times of shallot cultivars are very diverse. Therefore, studying the mechanism and regulatory genes of flowering is mandatory. The AcFT2 gene has a significant correlation with flowering in shallots. The present research aims to obtain information on the gene sequence, relative expression, and correlation of AcFT2 with flowering in shallots under vernalized and nonvernalized conditions. This study was conducted from August 2019 until September 2019 at the Center for Tropical Horticulture Studies, IPB University, Tajur, Bogor, Indonesia. Gene isolation and expression analyses were conducted from October 2019 to July 2020 at the Horticulture Laboratory, Gifu University, Japan. The shallot cultivar ‘Lokananta’ was subjected to vernalization at 8 °C for 6 weeks under nonvernalization treatment and then planted for 30 days for gene isolation. The AcFT2 gene sequence generated from the shallot cultivar ‘Lokananta’ was analyzed by using Geneious, MUSCLE, and Molecular Evolutionary Genetics Analysis. Gene expression was analyzed via qRT-PCR. Results showed that the AcFT2-like gene obtained from shallot had high homology with other FT genes from other plants, especially plants in the Allium genus. The shallot cultivar ‘Lokananta’ showed relatively similar expression as the partial shallot AcFT2-like gene under vernalization and nonvernalization treatments given that the number of umbel flowers did not significantly differ between both treatments.