Download molecular characterization and stress

Proceedings of the LX SIGA Annual Congress
Catania, Italy – 13/16 September, 2016
ISBN 978-88-904570-6-7
Poster Communication Abstract – 1.27
MOLECULAR CHARACTERIZATION AND STRESS-INDUCED
EXPRESSION PROFILING OF BZR TRANSCRIPTION FACTOR FAMILY
IN ZEA MAYS L.
TREVISAN S., RAVAZZOLO L., MANOLI A., FORESTAN C., QUAGGIOTTI S.,
VAROTTO S.
Department of Agronomy, Food, Natural Resources, Animals and Environment, University of
Padova (Italy)
brassinosteroids, maize, gene expression, abiotic stress
Brassinosteroids (BRs) are plant specific steroidal hormones that play diverse roles in
regulating a broad spectrum of plant growth and developmental processes. They regulate multiple
physiological functions including seed germination, cell elongation and division, senescence,
vascular-differentiation, reproduction, root development, photomorphogenesis and also respond to
various biotic and abiotic stresses. The identified regulatory steps in this network involve
transcription, protein–protein interaction and targeted protein destruction. Extensive research over
the years’ has established stress-impact-mitigating role of BRs and associated compounds in
different plants exposed to various abiotic stresses such as high temperature, low temperature in
terms of chilling as well as freezing. Reports are also available on the significance of BRs and
associated compounds in different plants exposed to salinity, drought, metals/metalloids and
organic pollutants. Some studies also suggested that BR treatment can promote plant resistance
against many pathogens, such as fungi, bacteria, and virus. Finally, BRs are reported to be effective
in reducing damage caused by pesticides and herbicide safening. In conclusion, BRs can act
efficiently in plants as immunomodulators when applied at the appropriate concentration and at the
correct stage of plant development, inducing a complex sequence of biochemical reactions such as
activation or suppression of key enzymatic reactions, induction of protein synthesis, and the
production of various chemical defence compounds. BRs open up new approaches for plant
resistance against hazardous environmental conditions.
BRASSINAZOLE-RESISTANT (BZR) transcription factors (TFs) are primarily well known
as positive regulators of BRs signal transduction in different plants. Being important regulators of
the BR synthesis, BZR TFs might have stress resistance related activities. However, no stress
resistance related functional study of BZR TFs has been reported in maize so far.
In this research a comprehensive genome-wide analysis was carried out in BES1/BZR1 gene
family in Zea mays L. BZR1 is a member of a small gene family that shares no appreciable
sequence similarity to any known proteins. This study identified 11 BZR TFs of Zea mays L.
(ZmBZR) from a genome-wide survey and characterized them through sequence analysis and
expression profiling in different tissues, against several abiotic stresses. Comparison of deduced
amino acid sequences reveals high degree of identity between the members of this protein family,
whit a high degree of similarity also observed with recognized BZRs of other plant species. The
tissue specific expression analyses revealed that the ZmBZR1 transcripts are differentially
expressed in various plant tissues, both under normal growth conditions and following stress
applications. Our detailed expression analysis of these genes is aimed at elucidating their role in
response to abiotic stress. Since BRs control many important agronomic traits, such as plant
architecture, seed yield, and tolerance to biotic as well as abiotic stresses the genetic manipulation
of BR biosynthesis or perception may lead to further increases in crop yields. Using these new
information, the quality and amount of plant-based food, fibre, and renewable raw materials may be
enhanced, without negative effects on the environment. Thus, these findings would be helpful in
resolving the complex regulatory mechanism of BZRs in stress resistance and further functional
genomics study of these potential TFs in different crops.