Loss of a highly conserved sterile alpha motif domain gene ( WEEP ) results in pendulous branch growth in peach trees

Significance Trees’ branches grow against the pull of gravity and toward light. Although gravity and light perception have been studied in model species, much is unknown about how trees detect and respond to these signals. Here, we report the identification of a gene (WEEP ) that controls lateral branch orientations and is directly or indirectly required for gravity responses in trees. Loss or reduction of WEEP expression produced branches that grow outward and downward and did not exhibit normal gravitropism responses when displaced. WEEP is conserved throughout the plant kingdom and may be involved in gravity perception. WEEP may also be a valuable target for breeding or engineering trees with improved shapes for agricultural and landscaping applications.