Flax (Linum usitatissimum L.) response to non-optimal soil acidity and zinc deficiency

Alexey A Dmitriev,Elena N Pushkova,Anna V Kudryavtseva,Marina I Smirnova,George S Krasnov,Nadezhda L Bolsheva,Liubov V Povkhova,Tatiana A Rozhmina,Parfait Kezimana,Nataliya V Melnikova,Olga V Muravenko,Roman O Novakovskiy,Maria S Fedorova,Anastasiya V Snezhkina,Alexander V Zyablitsin

doi:10.1186/s12870-019-1641-1

Alexey A Dmitriev, Elena N Pushkova + Show 13 more

Open Access

https://doi.org/10.1186/s12870-019-1641-1

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Abstract

BackgroundFlax (Linum usitatissimum L.) is grown for fiber and seed production. Unfavorable environments, such as nutrient deficiency and non-optimal soil acidity, decrease the quantity and quality of yield. Cultivation of tolerant to stress varieties can significantly reduce the crop losses. Understanding the mechanisms of flax response to the stresses and identification of resistance gene candidates will help in breeding of improved cultivars. In the present work, the response of flax plants to increased pH level and zinc (Zn) deficiency was studied.ResultsWe performed high-throughput transcriptome sequencing of two flax cultivars with diverse tolerance to increased pH level and Zn deficiency: Norlin (tolerant) and Mogilevsky (sensitive). Sixteen cDNA libraries were created from flax plants grown under control conditions, increased pH level, Zn deficiency, and both stresses simultaneously, and about 35 million reads were obtained for each experiment type. Unfavorable pH resulted in significantly stronger gene expression alterations compared to Zn deficiency. Ion homeostasis, oxidoreductase activity, cell wall, and response to stress Gene Ontology terms were the most affected by unfavorable pH and Zn deficiency both in tolerant and sensitive flax cultivars. Upregulation of genes encoding metal transporters was identified under increased pH level, Zn deficiency, and both stresses simultaneously. Under Zn deficiency, only in tolerant cultivar Norlin, we revealed the induction of several photosynthesis-related genes and, in this way, this tolerant genotype could overcome unfavorable effects of reduced Zn content.ConclusionsWe identified genes with expression alterations in flax under non-optimal soil acidity and Zn deficiency based on high-throughput sequencing data. These genes are involved in diverse processes, including ion transport, cell wall biogenesis, and photosynthesis, and could play an important role in flax response to the studied stresses. Moreover, genes with distinct expression changes between examined tolerant and sensitive genotypes could determine the mechanisms of flax tolerance to non-optimal soil acidity and Zn deficiency.

Highlights

Flax (Linum usitatissimum L.) is grown for fiber and seed production
Alterations in gene expression under strong alkaline stress were investigated in flax plants and genes related to response to biotic stimulus were found to be affected by alkalinity, while photosynthesis-related genes were affected by combined alkaline-salt stress [14]
Transcriptome sequencing and annotation To study the response of flax plants to non-optimal soil acidity and zinc deficiency, cultivars with different tolerance to the stress were selected on the basis of our previous investigations: tolerant Norlin and sensitive Mogilevsky [7]

Summary

Introduction

Flax (Linum usitatissimum L.) is grown for fiber and seed production. Unfavorable environments, such as nutrient deficiency and non-optimal soil acidity, decrease the quantity and quality of yield. Flax (Linum usitatissimum L.) is grown for fiber and seed production and used in textile, pharmaceutical, food, paint, and varnish industries [1] Unfavorable environments, such as nutrient deficiency and non-optimal soil acidity, decrease the quantity and quality of flax yield. High-throughput sequencing is intensively used for studying flax response to diverse stresses, including drought [4], alkalinity and salt [5], excess concentration of aluminum ions [6,7,8], imbalanced nutrition [9,10,11], Fusarium oxysporum infection [12, 13] These studies allowed the revelation of genes with expression alterations under the stresses and identification of processes on which the unfavorable conditions have the greatest impact. Alkaline stress disrupts uptake of metal micronutrients, including Zn and Fe, induced production of ROS, and results in alterations in levels of antioxidants, transcriptional factors, phytosiderophores, nicotianamine, photosynthesis-related and heat shock proteins in plants [35,36,37,38,39,40,41,42,43,44]

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