Comparative Proteomic Analysis Of Potato Seedling In Vitro Under Fe,Mn,or Zn Deficiency

Mineral nutrition iron(Fe),manganese(Mn)and zinc(Zn)are the essential trace elements for plant growth and development.They play an important role in various metabolic and physiological processes.The lack of Fe,Mn,or Zn not only severely restrict the growth and development of plants,but also lead to the decrease of their biomass production and product quality.Potato(Solanum tuberosum L.)as the world’s fourth largest food crop,in addition to rich in starch,but also contains human essential proteins,carbohydrates,fats,mineral salts,crude fiber and various vitamins.An experiment was carried out to study the effects of mineral deficiency on protein expression in potato,and to reveal the internal regulation mechanism.The test-tube seedlings of potato cultivars "Atlantic" were adopted in the experiment.Application of proteomics technique to study the changes of protein types and expression levels in potato under Fe,Mn,or Zn deficiency,it will help to understand the damage mechanism of mineral deficiency and the adaptation mechanism of potato from the whole and dynamic protein level.The detailed results were as following:1、Fe deficiency caused a significant decrease in chlorophyll content of potato leaves.The chlorophyll content decreased by 87% compared with the control in completely Fe deficiency.Comparative proteomics were used to analyze the differentially expressed proteins in potato leaves under Fe deficiency,and 146 differentially expressed proteins were identified.These proteins were classified into 10 functional categories according to their biological processes,involved in photosynthesis,metabolism,cell defense,molecular chaperones,redox,storage protein,cytoskeleton,transcription and translation,auxin response and substance transport.2、The chlorophyll content in potato leaves decreased gradually with the decrease of Mn concentration in the culture medium.Chlorophyll content was decreased by 5% and 16% respectively compared with the control under the 1 μM and 0 μM Mn concentration treatment.55 differentially expressed proteins were identified by comparative proteomics.These proteins were classified into 9 functional categories according to their biological processes,involved in photosynthesis,metabolism,auxin response,cell defense,redox,storage protein,transcription and translation,signal transduction and substance transport.3、The chlorophyll content in potato leaves was decreased by 9% compared with the control under the condition of Zn deficiency.Using comparative proteomics,42 differentially expressed proteins were identified.These proteins were classified into 8 functional categories according to their biological processes,involved in photosynthesis,metabolism,cell defense,redox,cytoskeleton,transcription and translation,auxin response and substance transport.The following conclusions are drawn from this experiment.Chlorophyll content decreased significantly under Fe,Mn,or Zn deficiency.This result suggests that Fe,Mn,or Zn deficiency could inhibit the synthesis of chlorophyll,which might lead to the decrease of photosynthetic efficiency and the change of carbohydrate accumulation.The expression of photosynthesis related proteins such as oxygen-evolving enhancer protein and ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit was significantly down regulated in Fe,Mn,or Zn deficiency.It may cause damage to photosynthesis and directly affect the process of photosynthetic carbon assimilation.The expression of PSI reaction center subunit and chloroplast ATP synthase was up-regulated under Mn or Zn deficiency,which will enhance the ability of photosynthesis to promote the absorption of nutrients.The expression of energy related enzymes was up-regulated in Fe,Mn,or Zn deficiency.Glycolysis and the TCA cycle were enhanced to adapt to nutrient stress.It is speculated that potato may need more reducing power and ATP under nutrient deficiency,and then improve the mechanism of nutrient acquisition and transportation.Fe,Mn,or Zn deficiency induced the defense system of potato.The expression of auxin-binding protein was significantly down regulated under Fe deficiency,which inhibited the growth and development of potato seedlings.This result is closely related to the physiological phenotype of potato plant dwarf under Fe deficiency.The expression of auxin-binding protein was up-regulated in response to zinc deficiency,so as to alleviate the inhibition of plant growth.