Salinity stress response of non‐transformed and AtCKX transgenic centaury (Centaurium erythraea Rafn.) shoots and roots grown in vitro

Abstract

Common centaury (Centaurium erythraea Rafn.) is a plant species that can inhabit saline soils. It is known as plant with high spontaneous regeneration potential in vitro. In present work we evaluated shoots and roots salinity tolerance of non transformed and three AtCKX transgenic centaury lines to graded NaCl concentrations (0, 50, 100, 150, 200 mM) in vitro. Overexpression of AtCKX genes in transgenic centaury plants resulted in an altered cytokinins (CKs) profile leading to a decline of bioactive CK levels and, at the same time, increased contents of storage CK forms, inactive CK forms and/or CK nucleotides. Significant increment of fresh shoot weight was obtained in shoots of non transformed and AtCKX1 transgenic line only on medium supplemented with 50 mM NaCl. However two analyzed AtCKX2 transgenic lines reduced shoot growth at all NaCl concentrations. In general, centaury roots showed higher tolerance to salinity than shoots. Non transformed and AtCKX1 transgenic lines tolerated up to 100 mM NaCl without change in frequency of regeneration and number of regenerated plants. Roots of two analyzed AtCKX2 transgenic lines showed different regeneration potential under salt stress. Regeneration of transgenic AtCKX2-26 shoots even at 200 mM NaCl was recorded. Salinity stress response of centaury shoots and roots was also evaluated at biochemical level. Free proline, malondialdehyde and hydrogen peroxide content as well as antioxidative enzymes activities were investigated in shoots and roots after 1, 2, 4 and 8 weeks. In general, adition of NaCl in culture medium elevated all biochemical parametars in centaury shoots and in roots. Considering that all analyzed AtCKX transgenic centaury lines showed altered salt tolerance to graded NaCl concentrations in vitro it can be assumed that CKs might be involved in plant defence to salt stress conditions.

Changes in Photosynthetic Pigments Content in Non-Transformed and AtCKX Transgenic Centaury (Centaurium erythraea Rafn) Shoots Grown under Salt Stress In Vitro

“…Šiler et al [36] described the effects of salinity on the in vitro growth and photosynthesis of centaury shoots. Recently, Trifunović-Momčilov et al [37] showed the physiological and biochemical aspects of the salinity stress response of non-transformed and AtCKX transgenic centaury shoots and roots grown in vitro. It was shown that centaury roots showed a higher salinity tolerance compared to shoots.…”

Phytochrome type B family: The abiotic stress responses signaller in plants

“…Many efforts have been made to alleviate salinity conditions through the improvement of soil quality (Hasini et al, 2020). However, physiological alterations in plants is also a potential tool to improve tolerance in these environmental conditions because salt stress activates complex downstream signalling pathways (Holm, Hardtke, Gaudet, & Deng, 2001; Trifunović‐Momčilov et al, 2020; Wani et al, 2020). These pathways are primarily related to the increase in ROS, which is associated with oxidative damage in salt‐stressed plants (Akyol, Yilmaz, Uzilday, Özgür Uzilday, & Türkan, 2020).…”

Somatic Embryogenesis in Centaurium erythraea Rafn—Current Status and Perspectives: A Review

“…The diversity of morphogenetic paths that C. erythraea can undergo in vitro has been compiled recently [ 28 ]. The vigorous morphogenic potential of the explants favors the use of centaury for genetic transformations [ 29 , 30 , 31 ], interspecific hybridization in vitro [ 32 , 33 , 34 ], functional studies on secondary metabolite synthesis in vitro [ 25 , 26 , 35 , 36 , 37 ], and stress physiology studies [ 38 , 39 ]. Overall, different aspects of C. erythraea’s in vitro development, physiology, pharmacology, and ecology have been studied for over20 years at the Department for Plant Physiology, Institute for Biological Research “Siniša Stanković”, University of Belgrade, resulting in 38 journal papers, 8 book chapters, and 9 masters and doctoral theses.…”