Grapevine red blotch disease: A comprehensive Q&A guide

Pleasenotethatthenumberedlistofheadingshasbeenremoved:Pleaseconfirmth is grapevine red blotch disease and what are its symptoms? Grapevine red blotch disease (GRBD) is a viral disease primarily affecting plants of Vitis spp. It was first described by UC Davis researchers in the mid-2000s, when they observed unusual red blotches on leaves (Fig 1A) and poor fruit ripening on "Cabernet Sauvignon" grapevines in Napa Valley, California [1]. The symptoms initially suggested a new strain of grapevine leafroll disease. Concurrently, similar symptoms were noticed in "Cabernet franc" vineyards in Lansing, New York. By 2012, a virus with a unique genome structure was identified in symptomatic grapevines [2,3], and by 2018, grapevine red blotch virus (GRBV) was confirmed as the causal agent of GRBD [4]. GRBV is taxonomically classified as a member of the Grablovirus genus in the Geminiviridae family. The virus has a single-stranded, circular DNA genome with 8 predicted bidirectional open reading frames (ORFs), 5 in the viral sense orientation and 3 in the complementary sense orientation. These ORFs encode proteins involved in various functions, including encapsulation of the viral genome, cell-to-cell movement, and suppression of host defenses.