Studies on involvement of Wrinkled1 transcription factor in the development of extra-long staple in cotton

In the present investigation, fiber transcriptome of Gossypium hirsutum producing short-fiber (JKC703, JKC737, JKC783) and long-fiber (JKC725, JKC777, Guazuncho 2) was compared with the transcriptome of extra-long fiber producing Gossypium barbadense (VH-84602). By meta-analysis, we identified 1431 differentially expressed genes among the genotypes of different fibre lengths. Of these, 574 genes were up-regulated while 844 were down regulated in G. barbadense as compared to G. hirsutum. Expression of 5 genes related to fiber development was tested in local germplasm of G. barbadense (Bar14/5) and used G. hirsutum (MNH 886) using real-time RT-PCR. G. arboreum (FDH786) was as a sample with unknown expression. Expression pattern of an ethylene responsive transcription factor wrinkeled-1 (wri1), a vacuolar processing enzyme (vpe) and eceriferum3 (cer3) gene showed close association with fiber lengths. Moreover, cotton wri1 expressed in apical-meristem and bolls and showed significantly higher expression in fiber of G. barbadense as compared to G. hirsutum and G. arboreum during development. Level of Transcription of writ was enhanced in fiber during ball development while it remained unchanged in fiber-less seeds.