Fig. 4.

General characteristics of the five identified GmLbs and two non-symbiotic GmHbs in soybean. (A) Phylogenetic analysis of Hb from different plant species. This phylogenetic tree includes seven Hbs from soybean (Glycine max), seven from common bean (Phaseolus vulgaris), 15 from Medicago truncatula, two from Arabidopsis thaliana, five from rice (Oryza sativa) and two from maize (Zea mays). It was constructed by the neighbour-joining method with 1000 bootstrap replicates in the MEGA 6.1 program. Haemoglobin proteins sorted into two clades, labelled clade I and clade II. Five GmLbs are highlighted by red triangles in the blue box, and two GmHbs are indicated by green circles in the red box. (B) Gene structures of symbiotic Lbs and non-symbiotic Hbs from soybean. White boxes represent exons, thin lines represent introns and black boxes represent 5′-/3′-UTRs. Numbers above introns indicate intron phases. Phase 0, 1 and 2 introns were defined as introns starting before the first, after the first and after the second nucleotide of a codon, respectively.