Plants respond to diverse signals by substantial changes in their morphogenetic plan. Changes in cell shape and size require remodeling of the existing plant cell wall to allow turgor-driven growth to occur. An important question is how plant cell wall remodeling is regulated to accommodate to a changing environment. In our preliminary results, HEAT SHOCK PROTIEN 70-1 (HSP70-1) was identified as novel regulator of cell wall function. Three semi-dominant hsp70-1shou5 alleles were identified as suppressors in fei1fei2 background. The FEI receptor-like kinases regulate cellulose biosynthesis in root tips, etiolated seedlings and seed coat mucilage. HSP70s act as ATPase-dependent chaperones and have diverse functions during plant growth and development and in plant response to different environmental signals. In the proposed research, we will further characterize the effect of the hsp70-1shou5 mutations on cell wall composition and the mechanism of cellulose biosynthesis. The effect of hsp70-1shou5 on plant transcriptome and metabolome will be studied in different developmental contexts (i.e. elongating roots and seed coat). Genetic interactions between hsp70-1shou5 and other cellulose related mutants will be examined. Downstream targets of HSP70-1 will be identified by EMS-induced mutagenesis of fei1fei2hsp70-1shou5 screened for enhancers and suppressors and by yeast two-hybrid screen for HSP70-1 interacting proteins. For a subset of candidate genes identified, their effect on HSP70 activity and cell wall function will be studied. In the proposed research we utilize the hsp70-1shou5 alleles to overcome functional redundancy and assign a new role for HSP70 in the regulation of cell wall remodeling and plant adaptation to changing environment. Improved understanding of the mechanism employed in cell wall remodeling will set the stage for the development of biotechnological tools aimed at the modification of industrial and agricultural traits-of-interest.