Genome-wide survey of B-box proteins in potato (Solanum tuberosum)—Identification, characterization and expression patterns during diurnal cycle, etiolation and de-etiolation

Abstract

Plant B-box domain proteins (BBX) mediate many light-influenced developmental processes including seedling photomorphogenesis, seed germination, shade avoidance and photoperiodic regulation of flowering. Despite the wide range of potential functions, the current knowledge regarding BBX proteins in major crop plants is scarce. In this study, we identify and characterize the StBBX gene family in potato, which is composed of 30 members, with regard to structural properties and expression profiles under diurnal cycle, etiolation and de-etiolations. Based on domain organization and phylogenetic relationships, StBBX genes have been classified into five groups. Using real-time quantitative PCR, we found that expression of most of them oscillates following a 24-h rhythm; however, large differences in expression profiles were observed between the genes regarding amplitude and position of the maximal and minimal expression levels in the day/night cycle. On the basis of the time-of-day/time-of-night, we distinguished three expression groups specifically expressed during the light and two during the dark phase. In addition, we showed that the expression of several StBBX genes is under the control of the circadian clock and that some others are specifically associated with the etiolation and de-etiolation conditions. Thus, we concluded that StBBX proteins are likely key players involved in the complex diurnal and circadian networks regulating plant development as a function of light conditions and day duration.

Light and ripening-regulated BBX protein-encoding genes in Solanum lycopersicum

“…The BBX TF family has been extensively studied in A. thaliana, whose proteins were classified into five groups accordingly to the domain structure 3,5 . Similar classification was reported for other species such as tomato 36 , potato 51 , rice 52 and grapevine 53 . However, not all provided a phylogeny with high branch support for the groupings and the lack of outgroup led the evolutionary history of the protein family ambiguous.…”

“…These results indicate that tomato BBX genes that belong to structure group IV and V are light responsive, like observed in A. thaliana 4 , and most are light-induced. The expression pattern of BBX encoding genes in Solanum tuberosum during de-etiolation was also addressed and the expression of most of the genes belonging to structural groups IV and V was modulated upon illumination of etiolated leaves 51 . This profile provides further evidences about a link between mRNA levels of BBX proteins from structure groups IV and V and plastid biogenesis and differentiation, revealing that they are affected, to some extent, by the light signalling cascade.…”

“…Over the past years, BBX protein family was surveyed in several species such as apple 64 , A. thaliana 4 , grapevine 53 , orchids 65 , pear 54 , rice 52 , potato 51 , Arachis duranensis 66 and tomato 36 , being classified in five groups accordingly to the domain composition of the proteins. The comprehensive phylogenetic analysis performed in this work (Fig.…”

Characterization of B-BOX gene family and their expression profiles under hormonal, abiotic and metal stresses in Poaceae plants

“…The previous study also found a similar number of BBX genes in the rice genome [14]. The number of BBX gene family members is pretty consistent among different crop plants, such as 30, 32, 29 and 30 BBX genes members were already identified in rice, Arabidopsis , tomato, and potato, respectively [1, 14, 33, 36]. The difference in the number of BBX genes among the crops plants is very less.…”

“…BBX gene family has been got more attention from the scientific community in the past couple of years. The genome-wide identification analysis of BBX genes has been already investigated in rice [14] and other important plants such as Arabidopsis , tomato, potato, pear and apple [1, 14, 33–36]. In this study, we also reported the genome-wide identification of BBX genes in five Poaceae species (maize, rice, sorghum, millet, and stiff brome), and their expression analysis under abiotic (cold, drought and salt), hormones (GA, ABA, SA and MeJA) and metal stresses (Cr, Cd, Ni and Fe) in rice.…”