Fig. 1

The three starch branching enzymes (SBEs) clades. A) A phylogenetic tree based on SBE DNA sequences from cereal and horticultural crops. The three clades correspond to the three classes of SBE, i.e., SBE1, SBE2, and SBE3. Cereals and horticultural crops diverged in each class. Within the class 2 SBEs, cereals form two clades, representing the ‘a’ and ‘b’ sub-isoforms (See Table 1). Only a few members of the predicted SBE3s were retrieved from cereals. This tree includes species from: rice, wheat, barley, sorghum, corn, millet, apple, banana, blueberry, rapeseed, cabbage, bok choy, citruses, cucumber, wax gourd, muskmelon, watermelon, pumpkins, date palm, durian, apricot, jujube, kiwifruit, lettuce, olive, papaya, peach, pear, pineapple, tomato, potato, pepper, eggplant, spinach, strawberry, sweet cherry, carrot, cassava, lotus root, radish, sweet potato, taro, and table grapes. B) A phylogenetic tree based on the predicted amino acid sequence of various SBE genes identified from horticultural crops showing sequence divergence. SBE1 evolved earlier than SBE2 and SBE3. SBE1 and SBE2 are more homologous to each other than to SBE3. SBEs from fruits, tuber & root, and leafy green were highlighted accordingly. SBE1 is absent in crops from the Brassicaceae family, apple, and European olive, while these species have two types of SBE2. Species presented include apple, banana, blueberry, rapeseed, wild cabbage, mustard, citruses, cucumber, wax gourd, muskmelon, watermelon, pumpkins, date palm, durian, apricot, jujube, kiwifruit, lettuce, olive, papaya, peach, pear, pineapple, tomato, potato, pepper, eggplant, spinach, strawberry, sweet cherry, carrot, cassava, lotus root, radish, sweet potato, taro, and table grapes. Sequences were retrieved from NCBI, Mainlab Bioinformatics Program (WSU) [52, 53] Sol Genomics Network [54], Genome Database for Vaccinium [55], CuGenDB [56, 57], Pineapple Genomics Database [58, 59] SpinachBase [60], KEGG [61], and Ensembl plants [62]. This tree was built by using the Neighbor-joining method with genetic distance (Jukes-Cantor Model) in the Geneious Prime® (Version 2020.2, https://www.geneious.com). The bootstrap test was performed with 1000 replicates. The figure generated was annotated using Microsoft® PowerPoint