Waterlogging affects plant morphology and the expression of key genes in tef (Eragrostis tef)

Abstract

Tef [Eragrostis tef (Zucc.) Trotter], an allotetraploid cereal that is a staple food to over 60 million people in the Horn of Africa, has a high nutritional content and is resistant to many biotic and abiotic stresses such as waterlogging and drought. Three tef genotypes, Alba, Tsedey, and Quncho, were subjected to waterlogging conditions and their growth, physiology, and change in transcript expression were measured with the goal of identifying targets for breeding cultivars with improved waterlogging tolerance. Root and shoot growth and dry weight were observed over 22 days. Stomatal conductance and chlorophyll and carotenoid contents were quantified. Microscopy was used to monitor changes in the stem cross sections. Illumina RNA sequencing was used to obtain the expression profiles of tef under flooding and control conditions and was verified using qPCR. Results indicated differences in growth between the three genotypes. Waterlogged Tsedey plants grew higher and had more root biomass than normally watered Tsedey plants. Quncho and Alba genotypes were more susceptible to the excess moisture stress. The effects of these changes were observed on the plant physiology. Among the three tested tef genotypes, Tsedey formed more aerenchyma than Alba and had accelerated growth under waterlogging. Tsedey and Quncho had constitutive aerenchyma. Genes affecting carbohydrate metabolism, cell growth, response to reactive oxygen species, transport, signaling, and stress responses were found to change under excess moisture stress. In general, these results show the presence of substantial anatomical and physiological differences among tef genotypes when waterlogged during the early growth stage.

Genome-Wide Analysis of Gene Expression Provides New Insights into Waterlogging Responses in Barley (Hordeum vulgare L.)

“…In addition, other genes involved in sucrose and starch metabolism and glycolysis were up-regulated in Yerong and Deder2 roots, such as α-amylase, SPS, phosphofructokinase and fructose-bisphosphate aldolase, NADP-GADH, and PK. These results were in agreement with recent studies in tef, a cereal grass [77], and maize [45].…”

Significance and prospects of an orphan crop tef

“…Such differential responses to waterlogging were also exhibited in the formation of aerenchyma in the roots. While Tsedey formed more aerenchyma than Alba and had accelerated growth under waterlogging, Tsedey and Quncho had constitutive aerenchyma (Cannarozzi et al 2018b).…”

“…Since tef is resilient to extreme environmental conditions, differentially regulated genes were investigated under drought and waterlogging conditions. A recent study showed that under excess moisture, genes affecting carbohydrate metabolism, cell growth, response to reactive oxygen species, transport, signaling, and stress responses were differentially regulated (Cannarozzi et al 2018b).…”

“…Tef is a versatile plant which performs better than cereal crops such as maize and wheat under both excess and scare moisture conditions. The physiological and anatomical mechanisms of response to waterlogging stress were recently investigated in three tef genotypes (Cannarozzi et al 2018b). According to these findings, while waterlogged Tsedey variety grew better than normally watered Tsedey plants, the other genotypes (Quncho and Alba) were susceptible to the excess moisture stress.…”

Genetic and genomic resources, and breeding for accelerating improvement of small millets: current status and future interventions

“…In proso millet, RNA-seq data was first reported by Yue et al [193], which served as an excellent sequence resource for gene discovery and marker development in this crop. Few reports also available in other millets, including barnyard millet for drought tolerance, and Fe and Zn accumulation [77], submergence tolerance [120]; and in teff for waterlogging [24], to understand the gene regulatory mechanisms in these crops. These studies underline the application of transcriptomics in identifying the gene repertoire underlying the traits-of-study, which can then be further characterized and used in crop improvement.…”