A mango ETHYLENE RESPONSE1(ETR1) gene, designated Mi ETR1 b, was isolated from the cotyledon of mango(Mangifera indica L. ‘Zihua’)using RT-PCR, and the 5′ and 3′ rapid amplificatio of c DNA ends. The full-length c DNA was 2 530 bp, with an open reading frame of 2 220 bp,and it encoded a putative protein of 739 amino acids. The genomic DNA sequence of Mi ETR1 b was 4 116 bp in length, having a 3 305 bp sequence from the start to terminator codon, containing six exons and fi e introns. The deduced amino acids possessed conserved domains of the GAF and HATPase_c superfamilies. A phylogenetic tree analysis indicated that Mi ETR1 b had the highest similarity to Mi ETR1 from M. indica and a high similarity to Cs ERS1, Dl ETR1, Tc ERS1 and Pt ETR1. Quantitative real-time PCR showed that Mi ETR1 b was expressed in the proximal and distal cut surfaces throughout the adventitious root formation period. Meanwhile, the expression of Mi ETR1 b in the distal cut surface was significant y up-regulated within 6–48 h. Pre-treatments with indole-3-butyric acid and 2,3,5-triiodobenzoic acid significant y downregulated Mi ETR1 b expression at 1 d and 6 h, respectively. However, more ethylene was produced from 12 to 24 h, while ethylene production decreased after 4 days of culturing. In conclusion, Mi ETR1 b might play an important role during the adventitious root formation of mango cotyledon segments, which is related to ethylene production. A mango ETHYLENE RESPONSE1 (ETR1) gene, designated Mi ETR1 b, was isolated from the cotyledon of mango (Mangifera indica L. ’Zihua’) using RT-PCR, and the 5 ’and 3’ rapid amplifications of c DNA ends. The genomic DNA sequence of Mi ETR1 b was 4 116 bp in length, having a 3 305 (full-length c DNA was 2 530 bp, with an open reading frame of 2 220 bp, and it encoded a putative protein of 739 amino acids. bp sequence from the start to terminator codon, containing six exons and fi e introns. The deduced amino acids possessed conserved domains of the GAF and HATPase_c superfamilies. A phylogenetic tree analysis indicated that Mi ETR1 b had the highest similarity to Mi ETR1 from M. indica and a high similarity to Cs ERS1, D1 ETR1, Tc ERS1 and Pt ETR1. Quantitative real-time PCR showed that Mi ETR1 b was expressed in the proximal and distal cutters throughout the adventitious root formation period. Meanwhile, the expression of Mi ETR1 b in the distal cut surface was significant y up-re gulated within 6-48 h. Pre-treatments with indole-3-butyric acid and 2,3,5-triiodobenzoic acid significantly y downregulated Mi ETR1 b expression at 1 d and 6 h, respectively. However, more ethylene was produced from 12 In conclusion, Mi ETR1 b might play an important role during the adventitious root formation of mango cotyledon segments, which is related to ethylene production.