Visiting Scientists

Renata Fuganti Pagliarini

Associated to Labex Scientist Alexandre Lima Nepomuceno

Quantitative gene expression evaluation of Maize circadian clock, drought and ABA responsive genes in toc1 mutant, under water deficit conditions

Research Team: Renata Fuganti Pagliarini (PhD), Frank Harmon (PhD), and Alexandre Nepomuceno (PhD).

Objective: Analyze in a maize toc1 mutant and in its wild type genotype, the expression pattern of circadian related genes and drought responsive genes along a 24h period under water deficit situations.

Aproach: A wild type genotype of maize (A632) and its toc1 mutant (FH370) were grown in a growth chamber at 14h/10h and 28oC/22oC day/night photoperiod and temperatures, respectively. Light intensity was 500 μmol/m2/s and air relative humidity 50%±5% under two drought treatments: 30% (mild/moderate) and 15% (severe) soil GH. Samples were harvested every 4h in a time course of 24h. RNA extraction started and qPCR reactions will be performed to quantify gene expression levels of key maize clock genes (ZmGIa, ZmGIb, ZmTOC1a, ZmTOC1b, LHYa and LHYb); and drought genes (PIS - Zea mays phosphatidylinositol synthase; RFP- Zea mays ring finger protein; DBP3 - Zea mays DRE-binding protein 3; DBP4 - Zea mays DRE-binding protein 4; dreb1- Zea mays DREB-like protein; ZmDREB2A - Zea mays mRNA for ERF/AP2 domain containing transcription factor; ERD4 - Zea mays early responsive to dehydration protein; dbf1- Zea mays DRE binding factor 1; dbf2 - Zea mays DRE binding factor 2 and RAB-17 - Maize gene drought responsive) present at Abscisic Acid (ABA) dependent and Independent pathways.

Results: Data just started to be collected, but by the end of this project we aimed to obtain results to help elucidate how circadian genes and circadian related genes interact with molecular mechanisms to respond to dehydration conditions, identifying putative functions of each gene. Also, we are looking to comprehend how ABA pathways and circadian clock converge to target tolerance defenses to drought. Identification of key genes involved on the circadian clock interactions with plant response/defense mechanisms to drought, may be used for genetic modifications to drought tolerance, or used on genome-wide selection approaches.