Stress signaling is central to plants which--as immobile organisms--have to endure environmental fluctuations that constantly interfere with vigorous growth. As a result, plant-specific, elaborate mechanisms have evolved to perceive and respond to stress conditions. Currently, these stress responses are plausibly being revealed to involve crosstalks with energy signaling pathways as any growth-limiting factor alters plant's energy status. Among these, autophagy, conventionally regarded as the mechanism whereby plants recycle and remobilize nutrients in bulk, has frequently been associated with stress responses. With the recent discoveries, however, autophagy has attained a novel role in stress signaling. In this review, major elements of abitoic stress signaling are summarized along with autophagy pathway, and in the light of recent discoveries, a putative, state-of-art role of autophagy is discussed.

The European hazelnut (Corylus avellana L.) is a tree crop of economic importance worldwide, but especially for northern Turkey, where the majority of production takes place. Hazelnut production is currently challenged by environmental stresses, such as a recent outbreak of severe powdery mildew disease; furthermore, allergy to hazelnuts is an increasing health concern in some regions. In order to provide a foundation for using the available hazelnut genetic resources for crop improvement, we produced a fully assembled genome sequence and annotation for a hazelnut species, from C. avellana cv. 'Tombul', one of the most important Turkish varieties. A hybrid sequencing strategy, combining short reads, long reads and proximity ligation methods, enabled us to resolve heterozygous regions and produce a high-quality 370-Mb assembly that agrees closely with cytogenetic studies and genetic maps of the 11 C. avellana chromosomes, and covers 97.8% of the estimated genome size. The genome includes 27 270 high-confidence protein-coding genes, over 20 000 of which were functionally annotated based on homology with known plant proteins. We focused particularly on gene families encoding hazelnut allergens, and the Mildew resistance Locus O (MLO) proteins that are an important susceptibility factor for powdery mildew. The complete assembly enabled us to differentiate between members of these families and to identify homologues that may be important in mildew disease and hazelnut allergy. These findings provide examples of how the genome can be used to guide research and to develop effective strategies for crop improvement in C. avellana.

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