Ionome Changes Of Arabidopsis Thaliana Reproduction Organs During Flower Development

Mineral nutrients are essential for plant growth and development including reproduction.To acquire appropriate macro-and micro-elements,plants have evolved complex system including functional specialized cell types,cellular structures and transport facilities.Flower development of A.thaliana has been extensively studied,but the steady-state changes of mineral nutrients and their roles during this process remain largely unclear,mainly due to limitation of obtaining enough materials at the early stage of flowering.In this study,we take advantage of a floral induction system to overcome this problem to monitor the temporal ionome changes during flower development from initiation to maturation.We first analyzed transcriptome changes of the genes encoding ion transporters.We found that most significant transcriptional changes of the transporters occur at the time between 5th to 7th day after flower initiation.Consistently,the major ionome changes were observed at the same time,indicating that this time is a key transition stage for nutrients requirement.We next observed the vacuole development changes during flower development and found that most significant size and quantity changes also occur at the time between 5th to 7th day after flower initiation,which means vacuole may acts as crucial compartmentalization part for changing ions.To further illustrate the possible genes evolved in the process of flowering,we next investigate one of the Na+transporter gene,AtHKT1,which has a significant expression change at the late stage of flowering.We found that Na+ transporter AtHKT1 plays a crucial role in controlling Na+content of flower.AtHKT1 is highly expressed in vascular tissues of Arabidopsis reproductive organs.Mutation of AtHKT1 showed sterile phenotype following 100 mM NaCl for retardation of filament extention and female tissue damage resulted from high Na+.Our results illustrate the ionome changes during flower development and emphasize the significance of moderate Na+ in flower tissue controlled by AtHKT1.