Rooting mechanism of Dendrocalamus brandisii branch and main differences in rooting ability in three different bamboo species.

Adventitious root (AR) growth is vital for mass propagation of bamboo, and there is a significant difference in the rooting ability among different bamboo species. The differences of AR differentiation from the bamboo branch were undefined. In this study, it was found that the thickness and lignification degrees of the cortex were closely related to the degree of rooting difficulty of the branch base in different bamboo species. The inner cortical cells restored their division ability and further differentiated AR primordium in Dendrocalamus brandisii. Indole-3-acetic acid (IAA) and jasmonic acid (JA) played a crucial role in the development of ARs, and further IAA and JA treatment analysis indicated that only low concentration hormones could enhance AR differentiation. DbCRL1 and DbAOS1 were defined to be related to the AR differentiation, and their positive functions were validated in rice. DbAOS1 exhibited an ability to independently enhance and activate ANTHRANILATE SYNTHASE in the auxin production pathway. DbCRL1 could interact with DbWOX11 in vivo and in vitro, wherein they promote AR differentiation synergistically. These findings revealed the differences of AR differentiation in the branch and provided new insights into the rooting mechanism of D. brandisii branch.