Transcriptomic profiling of heat-stress response in potato periderm

Abstract

Potato (Solanum tuberosum L.) periderm is composed of the meristematic phellogen that gives rise to an external layer of suberized phellem cells (the skin) and the internal parenchyma-like phelloderm. The continuous addition of new skin layers and the sloughing of old surface layers during tuber maturation results in smooth, shiny skin. However, smooth-skin varieties frequently develop unsightly russeting in response to high soil temperatures. Microscopic observation of microtubers exposed to high temperatures (37 degrees C) suggested heat-enhanced development and accumulation of suberized skin-cell layers. To identify the genes involved in the periderm response to heat stress, skin and phelloderm samples collected separately from immature tubers exposed to high soil temperatures (33 degrees C) and controls were subjected to transcriptome profiling using a potato cDNA array. As expected, the major functional group that was differentially expressed in both skin and phelloderm consisted of stress-related genes; however, while the major up-regulated phelloderm genes coded for heat-shock proteins, many of the skin's most up-regulated sequences were similar to genes involved in the development of protective/symbiotic membranes during plant-microbe interactions. The primary activities regulated by differentially expressed peridermal transcription factors were response to stress (33%) and cell proliferation and differentiation (28%), possibly reflecting the major processes occurring in the heat-treated periderm and implying the integrated activity of the stress response and tissue development. Accumulating data suggest that the periderm, a defensive tissue, responds to heat stress by enhancing the production and accumulation of periderm/skin layers to create a thick protective cover. Skin russeting may be an indirect outcome; upon continued expansion of the tuber, the inflexible skin cracks while new layers are produced below it, resulting in a rough skin texture.

How does Cariniana estrellensis respond to different irradiance levels?

“…The greater thickening of the secondary xylem and periderm under partial shading indicates, respectively, higher water conductance (Schuetz et al 2013) and the protection of internal stem structures against heat (Ginzberg et al 2009). The thicker secondary phloem indicates greater photo assimilates transport capacity (Gaburro et al 2014) from organ source to drain, confirmed by the higher concentration of glucose and fructose in the leaves.…”

Efficiency of selection in early generations of potato families with a view toward heat tolerance

“…Greater than ideal temperatures bring about multiple physiological, biochemical, and molecular processes of the potato plant (Hancock et al 2013). Thus, heat stress delays tuber development, reduces production and dry matter content of the tubers, increases respiration and the partitioning of photoassimilates to the plant shoots (Levy and Veilleux 2007), negatively affects the qualitative appearance of the tubers (Ginzberg et al 2009), and increases the rate of physiological disorders (Benites and Pinto 2011). Thus, studies that seek to obtain heat tolerant potato clones should be a priority in Brazilian breeding programs, and efforts have been made in this direction (Benites and Pinto 2011).…”

miRNA profiling in leaf and cork tissues of Quercus suber reveals novel miRNAs and tissue-specific expression patterns

“…In that work, a list of candidate genes isolated from cork tissues were identified including genes for the synthesis, transport, and polymerization of suberin monomers as well as a number of regulatory genes including members of the NO APICAL MERISTEM (NAM), MYB and WRKY transcription factor families with putative functions in meristem identity and cork differentiation. Since then, a number of studies have been published characterizing the role of a few selected candidate orthologues in potato tuber suberin formation by reverse genetics approaches (Serra et al 2010a;Serra et al 2010b;Serra et al 2009a;Serra et al 2009b) and identifying additional candidates in potato tuber periderm (Barel and Ginzberg 2008;Chaves et al 2009;Ginzberg et al 2009;Soler et al 2011). Despite the remarkable ability of cork oak to produce cork, potato has been the preferred model to study these processes since it is more amenable to in vitro manipulation and transformation having, in addition, its genome fully sequenced (Xu et al 2011).…”