Abstract:
Morphogenesis in plant development has been of great interest for researchers
engaged in plant physiological studies. Complex tissue types of higher plants make
these studies difficult. A lot of work has been done on the development of plants but,
we still lack crucial information on gene regulatory networks (GRN) involved in
gametophytic development. Physcomitrella patens (moss) is a simple, non-vascular
plant belonging to bryophyte family shows relatively simple tissue types but still
reflects all major developmental patterns of higher plants. We focused on the GRN
involved in bud formation and its transition to gametophore in moss. In this regard,
tobacco retrotransposon (Tnt1) and T-DNA was chosen as insertional mutagenesis
tool to develop mutants in moss. At the time we started our study, there was no
literature available on the protocol for Tnt1 retrotransposon use in moss. We
established Tnt1 as mutagenesis tool in moss. In our study, TAIL-PCR analysis
showed that Tnt1 retrotransposon has specificity to the gene rich region. A recent
study on the use of Tnt1 as mutagenesis tool in moss, supports our data (Vives et al.,
2016). We found that LTR promoter of (Tnt1) retrotransposon and modified LTR
promoter (mLTR) were inducible by CuCl2, Auxin (IAA), Salicylic acid treatments and
temperature gradient. Our forward genetic screen yielded a mutant deficient in bud
development (LTR-GUS line 7) and two mutants showing less gametophore formation
(LTR-GUS line 4 and Tnt1 line 13). In our analysis, Tnt1 line 13 was found to be
deficient in sensing gravity. Overall, this study shows that Tnt1 can be efficiently used
as a mutagenesis tool in moss. Further study on these mutant lines will throw light on
genes involved in bud and gametophore development.
