WUCHEL Gene Family: Transcription Factor-WOX2 As A Early Genetic Marker of Gene Expression During Induction of Somatic Embryogenesis: An updated Review

WUSCHEL-related homeobox (WOX) is a large group of transcription factors (WOX1-WOX14) specifically found in plants. WUSCHEL homeobox 2 (WOX2) is important for regulating many aspects of plant somatic embryogenesis. Transcription factors (TFs) are master regulators involved in controlling different cellular and biological functions as well as diverse signaling pathways in plant growth and development. The transcription factors like WUSCHEL-RELATED HOMEOBOX (WOX2) are crucial for maintaining cellular totipotency and regulating the developmental pathways of somatic embryogenesis. The induction of somatic embryogenesis using shoot apical thin layers has been successful by Malabadi and co-workers in few conifers such as Pinus roxburghii, Pinus kesiya, Pinus wallichina, Pinus patula, and Pinus sylvestrus (Scots pine). Furthermore, the detection and expression of PrWOX2, and PcWOX2 in embryogenic cultures imitated from shoot tip thin layers of mature trees of P. roxburghii and Lodgepole pine (Pinus contorta) could be used as a genetic marker for the identification of embryogenic tissue in pines. The findings from this study based on the molecular assessment, suggested that the cell lines derived from bud cultures were truly embryogenic, not just cells that imitate embryogenic cultures (EC) in morphology. Moreover, these experimental observations also suggest that Pr WOX2 and PcWOX2 could be used as an early genetic marker to discriminate embryogenic cultures from callus initiated from thin cell layers of mature trees of conifers. The research contribution  of pine tissue culture work by Indian plant biotechnology Stalwarts, Professor RN Konar, Nagamani, P Mahshwari, Professor Pramod Tandon, Professor Chittaranjan R. Deb, Professor Hiranjit Choudhary, Dr. Sarita Arya, Dr. ID Arya, Dr. RK Kalia, and Dr. Rajani S. Nadagouda has been updated and discussed. The Government of India has awarded Professor Pramod Tandon the fourth highest civilian honour Padma Sri in 2009, for his outstanding contribution to plant science. However, commercialization of pine tissue culture work in India is still facing problems and major bottleneck due to many reasons. Applications of cell sorting techniques, embryogenic cell culture identification by Artificial Intelligence (AI) should be applied for the future studies of initiatation of embryogenic cultures using thin cell layers of shoot apical domes of mature conifers.