Proteomics Evidence of a Systemic Response to Desiccation in the Resurrection Plant Haberlea rhodopensis

Abstract

Global warming and drought stress are expected to have a negative impact on agricultural productivity. Desiccation-tolerant species, which are able to tolerate the almost complete desiccation of their vegetative tissues, are appropriate models to study extreme drought tolerance and identify novel approaches to improve the resistance of crops to drought stress. In the present study, to better understand what makes resurrection plants extremely tolerant to drought, we performed transmission electron microscopy and integrative large-scale proteomics, including organellar and phosphorylation proteomics, and combined these investigations with previously published transcriptomic and metabolomics data from the resurrection plant Haberlea rhodopensis. The results revealed new evidence about organelle and cell preservation, posttranscriptional and posttranslational regulation, photosynthesis, primary metabolism, autophagy, and cell death in response to desiccation in H. rhodopensis. Different protective intrinsically disordered proteins, such as late embryogenesis abundant (LEA) proteins, thaumatin-like proteins (TLPs), and heat shock proteins (HSPs), were detected. We also found a constitutively abundant dehydrin in H. rhodopensis whose phosphorylation levels increased under stress in the chloroplast fraction. This integrative multi-omics analysis revealed a systemic response to desiccation in H. rhodopensis and certain targets for further genomic and evolutionary studies on DT mechanisms and genetic engineering towards the improvement of drought tolerance in crops.

Protein Changes in Shade and Sun Haberlea rhodopensis Leaves during Dehydration at Optimal and Low Temperatures

“…48 and 14 kDa bands showing density changes upon desiccation. Among the de novo accumulating proteins, multiple polypeptides identified by Mladenov et al [ 35 ] were also detected (e.g., ELIP, UDP-apiose/xylose synthase, pectin methylesterase). Generally, we found that an increased abundance of polypeptide bands on 1D SDS-PAGE primarily appeared in the molecular weight region below 55 kDa, thus proving to be smaller than RbcL.…”

“…Accumulation of stress-induced proteins is among the main defense mechanisms in resurrection plants upon drought stress [ 34 ]. The recent holistic proteomic analysis of Mladenov et al [ 35 ] indicated the accumulation of multiple proteins associated with drought stress in H. rhodopensis : cell wall biosynthesis enzymes (e.g., UDP-apiose/xylose synthase, pectin methylesterase), mitochondrial transporters (e.g., mitochondrial outer membrane voltage-dependent anion channel), autophagy-associated elements (e.g., autophagy-associated gene proteins 3 and 9), oxidative stress protection (Cu/Zn-SOD), and protective proteins (20 kDa dehydrin, ELIP1), among others. Previously, Gechev et al [ 36 ] reported the expression of HSP genes upon drought stress in H. rhodopensis .…”

“…Although Mladenov et al [ 35 ] performed a detailed analysis of the proteome of H. rhodopensis , protein isolation and separation techniques may induce a selective loss of proteins [ 37 ]. Thus, here we applied a simple SDS-PAGE 1D separation of the leaf total proteome and analyzed approx.…”

“…Altered sugar metabolism upon desiccation has been indicated before [ 36 , 48 , 49 ] and was connected with the formation of secondary vacuoles [ 29 ]. However, the alterations in the carbohydrate metabolism also affect the biosynthesis and composition of cell wall carbohydrates [ 35 ]. Modification of the structure of cell wall polysaccharides plays a crucial role in the dehydration process in resurrection plants [ 34 ].…”

Differential Accumulation of sHSPs Isoforms during Desiccation of the Resurrection Plant Haberlea rhodopensis Friv. under Optimal and High Temperature

“…Differences in the pIs of sHSPs with the same molecular weight might be due to post-translational modifications of the proteins, with phosphorylation being the most common. The important role of protein phosphorylation in resurrection plants has been suggested [ 55 , 56 ].…”