Expression and functions of proteases in vascular tissues

Abstract

With the emergence of new models for wood formation and the increasing emphasis on improving the efficiency of cellulosic biofuel production, research on vascular tissue biology has intensified in recent years. Some of the most active areas of research focus on manipulating activity of enzymes in the cellulose, hemicellulose, pectin and lignin pathways. In addition, great strides have been made in the characterization of transcriptional networks controlling genes that affect differentiation, secondary cell wall synthesis and programmed cell death in xylem. Less attention has been devoted to the characterization of proteases that may be important regulators of post-translational events that affect vascular cell differentiation and function and cell wall composition. Several genes for proteases and components of the ubiquitin/26S proteasome pathway are upregulated in xylem and phloem and in cell culture systems for studying the differentiation of xylem tracheary elements (TEs). Although small molecule protease inhibitors have been used to explore the roles of proteases during the differentiation of cultured TEs, only a small number of vascular tissue-associated protease genes have been directly tested to determine whether they play roles in vascular tissue biology. In this report, we review roles for proteases in vascular cell differentiation and function as determined through the use of protease inhibitors and genetic analyses and conclude by identifying opportunities for future research in this area.

Graft union formation in grapevine induces transcriptional changes related to cell wall modification, wounding, hormone signalling, and secondary metabolism

“…Additionally, the up-regulation of genes encoding phloem filament-associated proteins suggests that new phloem cells were being produced. The up-regulation of subtilases, as well as other classes of proteases, could be related to vascular tissue differentiation and development during the beginning of the spring growth cycle (Petzold et al , 2012). The up-regulation of proteases has been widely reported in transcriptomic studies of xylem differentiation (e.g.…”

Xylogenesis in zinnia (Zinnia elegans) cell cultures: unravelling the regulatory steps in a complex developmental programmed cell death event

“…However, in addition to vacuole expansion and collapse and cellular autolysis, typical for vacuolar cell death, also other PCD features have been observed: nucleus condensation, oxidative stress-related processes, laddering type of DNA fragmentation and activation of PCD-associated enzymes such as CLPs (Bonneau et al 2008; Twumasi et al 2010a; Woltering 2010; Han et al 2012; Petzold et al 2012 and references therein). This suggests that zinnia TE differentiation may involve signalling pathways of both vacuolar and necrotic PCD classes.…”

Comparison of tissue deterioration of ripening banana fruit (Musa spp., AAA group, Cavendish subgroup) under chilling and non‐chilling temperatures

“…As observed in the light microscopical images, deeper cell layers in banana peel contain a large proportion of vascular tissue. Petzold et al . described the critical role of proteases in differentiation and function of vascular tissues.…”

“…As observed in the light microscopical images, deeper cell layers in banana peel contain a large proportion of vascular tissue. Petzold et al 33 described the critical role wileyonlinelibrary.com/jsfa of proteases in differentiation and function of vascular tissues. They suggested non-redundant and redundant functions of individual proteases, including serine and cysteine proteases and the ubiquitin/26S proteasome pathway.…”