Examining traits that link to increased tolerance to iron deficiency in soybean

Crop Soybean
Start Date2018
End Date2022
Principal InvestigatorStasolla, Claudio, University of Manitoba
Total Project Funding$195,350
ReportStasolla – Iron deficiency – Annual Report 2020

Research Objectives

1. Screening commercial varieties of soybean for IDC As an extension of the previously MPSG-funded project by Dr. Hou, this objective will screen novel soybean varieties for IDC using a hydroponic system in which the level of iron is experimentally manipulated. The degree of chlorosis and chlorophyll content will be evaluated at the V1, V2, and V3 stage of development. Some of the varieties exhibiting the highest and the lowest IDC will be further used to assess correlations between the level of phytoglobins (scavengers of NO) and the cellular redox state with plant response. 2. Improving tolerance to iron deficiency in soybean plants through manipulations of nitric oxide (NO) and the cellular redox state Based on previous reports in other species suggesting that NO (Graziano, 2002) and reduced redox state (Ramirez et al., 2013) contribute to protect plants against the detrimental effect of insufficient iron supply, the level of NO will be elevated and the cellular redox reduced (through pharmacological foliar applications or seed priming) in an effort to enhance the response of plants to iron deficiency. Efficient methodologies to reduce the effects of iron deficiency will be provided. 3. Assessing the use of phytoglobin as a marker for tolerance to iron deficiency Phytoglobin is an effective NO scavenger (Hill, 2012) and also influences the cellular redox state (Igamberdiev et al., 2006). In addition, NO enhances internal iron availability (Graziano et al., 2002). Based on these studies it is anticipated that phytoglobin will influence IDC either through scavenging of NO or increased production of antioxidants. This objective will test if phytoglobin is a marker to screen and predict the behaviour of cultivars to iron deficiency. This information could be used to develop simple tests to aid selection in breeding programs.

Project Description

This research aims at developing strategies to improve screening processes for assessing iron deficiency chlorosis (IDC) in soybean and to enhance tolerance in existing cultivars using an understanding of the physiological processes associated with IDC.

Tolerance to IDC will be assessed in soybean commercial varieties, and their growth behaviour to insufficient iron conditions will be examined in relation to their ability to accumulate nitric oxide and alter the cellular redox state. These metabolic events have been linked to IDC tolerance in other species. Based on these results, strategies to ameliorate IDC tolerance in susceptible varieties will be developed by exogenous applications of compounds modulating the level of nitric oxide or altering the cellular redox state.

Treatments will be applied through foliar applications or seed priming (soaking the seeds with the desired compounds), effective delivery methods employed in many studies. A genetic approach, using the nitric oxide scavenger phytoglobin, will also be undertaken to modulate the levels of nitric oxide and alter the cellular redox state to evaluate the response of the plants to iron deficiency. If successful, this research will provide simple methodologies to alleviate IDC through pharmacological applications, as well as a reliable molecular marker, i.e. phytoglobin, to be used in screening programs aiming at selecting for IDC tolerance.