HB4 wheat (event IND-ØØ412-7) was produced by biolistic transformation of sterile embryos of wheat cv. Cadenza with two different plasmids: pIND4-HB4 and pIND4-Bar. pIND4-HB4 contained the modified version 2 of the Helianthus annuus homeobox 4 gene HB4 (called HaHB4.2) and pIND4-Bar contained the bar gene of Streptomyces hygroscopicus.

HB4, a member of the HD-Zip sub-family I, codes for a transcription factor involved in the tolerance to environmental stress. HB4 wheat expresses HB4 and therefore is more tolerant to environmental stresses, e.g. drought stress, and produces higher yield in production environments of low productivity potential.

The bar gene confers resistance to glufosinate-containing herbicides.

Both genes, HB4 and bar, are expressed under the control of the promoter (including the first intron) of the ubi1 gene from maize and the nos terminator from Agrobacterium tumefaciens.

The number of insertions and whether or not vector backbone sequences are integrated is unclear.

Sources: Gonzalez et al. (2019). Field-grown transgenic wheat expressing the sunflower gene HaHB4 significantly outyields the wild type. Journal Of Experimental Botany, 70(5):1669-1681.