FUNCTIONAL ANALYSIS OF MAIZE GENES INVOLVED IN SEEDLING DEVELOPMENT AND IN PLANT ¿ ENVIRONMENT INTERACTION
Tesi di Dottorato
Data di Pubblicazione:
2018
Citazione:
FUNCTIONAL ANALYSIS OF MAIZE GENES INVOLVED IN SEEDLING DEVELOPMENT AND IN PLANT ¿ ENVIRONMENT INTERACTION / M. Zilio ; tutor: G. Consonni, F. Nocito ; coordinatore: D. Bassi. DIPARTIMENTO DI SCIENZE AGRARIE E AMBIENTALI - PRODUZIONE, TERRITORIO, AGROENERGIA, 2018 Jan 19. 30. ciclo, Anno Accademico 2017. [10.13130/zilio-massimo_phd2018-01-19].
Abstract:
Maize is one of the most important cultivated plants on a world scale, with a total production which exceeds one billion tonnes per year (FAOSTAT 2017). It is an important human food source in many parts of the world, but is also intensely exploited for biofuel and feed production. Furthermore, maize is also a model plant for research studies in the field of biology and genetics. For these reasons, maize is one of the most intensively studied crops, with the aim of improving its productivity, which in the USA has increased nearly five times since the 1940s. This dramatic yield improvement is due to the development and widespread use of new farming technologies. An important role was played by genetic improvement, with the use of highly productive maize hybrids and, more recently, biotechnology.
However, the increases in annual productivity of maize and the other main crops exploited for food production seem to have reached a stall phase in recent years.
It has been estimated that the world population will increase from 7.5 to 9.7 billion people by 2050. To meet the food needs of the increasing population, and to satisfy diets that will include more meat, according to the Food and Agricultural Organization (FAO), worldwide crop production will have to increase by 70%. It is a tough task, made even more difficult by the fact that the worldwide area of cultivable soil is decreasing as a consequence of increasing urbanization and climate change.
To reach the target, new strategies are required, which will include multiple and integrated approaches, among them genetic improvement. One of the main challenges will be to develop new plant ideotypes that will combine the capability to tolerate biotic and abiotic stress with no reduction in yield.
Within this perspective, the work carried out in this thesis project was aimed at understanding the molecular mechanisms involved in plant response to environmental factors.
The work was organized in two parts, which are presented here in two different chapters. Both chapters are focused on genes that control plant development as well as plant- environment interactions.
The first chapter deals with the study of the genetic regulation of cuticle deposition in maize. The cuticle is an important plant organ and constitutes the first barrier against many environmental stresses, including water deprivation and pathogen interaction. The cuticle is produced by epidermal cells and is composed of a complex array of long chain hydrocarbons, constantly deposed on the aerial surface for all the plant’s life.
To investigate the cuticle biosynthesis process in maize, our strategy was based on the functional characterization of ZmMYB94, also known as fused leaves 1 (fdl1). This gene encodes a transcription factor of the R2R3-MYB subfamily, expressed in embryo, seedling and silk tissues. A mutant in this gene, referred to as fdl1-1, was available for this study. It originated from the insertion of an Enhancer/Suppressor (En/Spm) element in the third exon of the ZmMYB94 gene. The mutation has a pleiotropic effect on seedling development. The main features of fdl1-1 mutant plants are irregular coleoptile opening and the presence of regions of adhesion between the coleoptile and the first leaf and between the first and second leaves.
Deeper studies of the fdl1-1 mutant, performed by electron microscopy analysis, showed that, in regions of organ adhesion, cuticle was absent and, on the epidermal surface, epicuticular wax deposition occurred irregularly. These observations led to the hypothesis that phenotypic alterations observed in the mutant seedlings may be attributable to defects in the cuticle-related biosynthetic pathways.
To gain insight into the role of fdl1 in controlling cuticle formati
Tipologia IRIS:
Tesi di dottorato
Keywords:
maize; genetics; cuticle; drought; myb; brassinosteroids; fusarium
Elenco autori:
M. Zilio
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