Expression of Root-Related Transcription Factors Associated with Flooding Tolerance of Soybean (Glycine max)

Abstract

Much research has been conducted on the changes in gene expression of the model plant Arabidopsis to low-oxygen stress. Flooding results in a low oxygen environment in the root zone. However, there is ample evidence that tolerance to soil flooding is more than tolerance to low oxygen alone. In this study, we investigated the physiological response and differential expression of root-related transcription factors (TFs) associated with the tolerance of soybean plants to soil flooding. Differential responses of PI408105A and S99-2281 plants to ten days of soil flooding were evaluated at physiological, morphological and anatomical levels. Gene expression underlying the tolerance response was investigated using qRT-PCR of root-related TFs, known anaerobic genes, and housekeeping genes. Biomass of flood-sensitive S99-2281 roots remained unchanged during the entire 10 days of flooding. Flood-tolerant PI408105A plants exhibited recovery of root growth after 3 days of flooding. Flooding induced the development of aerenchyma and adventitious roots more rapidly in the flood-tolerant than the flood-sensitive genotype. Roots of tolerant plants also contained more ATP than roots of sensitive plants at the 7th and 10th days of flooding. Quantitative transcript analysis identified 132 genes differentially expressed between the two genotypes at one or more time points of flooding. Expression of genes related to the ethylene biosynthesis pathway and formation of adventitious roots was induced earlier and to higher levels in roots of the flood-tolerant genotype. Three potential flood-tolerance TFs which were differentially expressed between the two genotypes during the entire 10-day flooding duration were identified. This study confirmed the expression of anaerobic genes in response to soil flooding. Additionally, the differential expression of TFs associated with soil flooding tolerance was not qualitative but quantitative and temporal. Functional analyses of these genes will be necessary to reveal their potential to enhance flooding tolerance of soybean cultivars.

Understanding genetic control of root system architecture in soybean: Insights into the genetic basis of lateral root number

“…As the restriction enzymes used in developing SoySNP50K array might have cleaved the genomic position that harbour this LRN gene. The first nonsynonymous SNP (Mut 1) that alters amino acid from serine to alanine was detected in 15 elite soybean accessions of Germplasm Pool II, which includes PI 416937 and PI 408105A known to produce high LRNs and perform better under drought (Pantalone, Burton, & Carter, ) and flooding (Valliyodan et al, ) stresses.…”

“…The natural genetic variation in root traits is a largely untapped resource that has had limited use as selection criteria in crop breeding programs (Lynch & Brown, ; York, Nord, & Lynch, ). Soybean plant introductions (PIs) 416937 (King, Purcell, & Brye, ; Prince, Song, et al, ; Prince, Murphy, et al, ) and 408105A (Valliyodan et al, ) were shown to exhibit profuse fibrous root systems, but no genes controlling the observed morphological variations were identified.…”

A major natural genetic variation associated with root system architecture and plasticity improves waterlogging tolerance and yield in soybean

“…Roots directly face damage during waterlogging stress due to cellular anoxia, with root meristems showing particular vulnerability (Kozlowski, ; Valliyodan et al, ; Valliyodan et al, ). Damaged root system fails in water and nutrient uptake, especially after waterlogging (soil drying; Kramer & Jackson, ).…”

Phenotypic variation in root development of 162 soybean accessions under hypoxia condition at the seedling stage

“…Root growth and morphology under waterlogging and the resulting hypoxia during these early stages have been verified in soil and hydroponic cultivation systems. In soil cultivation, root dry weight (RDW) had decreased significantly by 7 days of waterlogging at the V1 stage (Sallam & Scott, 1987;Valliyodan et al, 2014;Yamane & Iijima, 2016). Although genetic variation in the response to waterlogging at the flowering stage was observed in various soybean cultivars (Rhine et al, 2010;VanToai et al, 1994VanToai et al, , 2010, few researchers have screened cultivars by root morphology under waterlogging during the early vegetative stage.…”