Transcriptome Dynamics of Rooting Zone and Leaves during In Vitro Adventitious Root Formation in Eucalyptus nitens

ACEVEDO RAÚL M.; ACUÑA CINTIA; SANSBERRO PEDRO A.; AYALA PAULA G.; RIVAROLA MAXIMO L.; GONZALEZ ANA M.; LUNA CLAUDIA V.; MARCUCCI POLTRI SUSANA

Plants

Editorial Board

Lugar: Basel, Switzerland; Año: 2022 vol. 11

2223-7747

Wood properties and agronomic traits associated with fast growth and frost tolerancemake Eucalyptus nitens a valuable forest alternative. However, the rapid age‐related decline in theadventitious root (AR) formation (herein, meaning induction, initiation, and expression stages) lim‐its its propagation. We analyzed transcriptomic profile variation in leaves and stem bases duringAR induction of microcuttings to elucidate the molecular mechanisms involved in AR formation. Inaddition, we quantified expressions of candidate genes associated with recalcitrance. We delimitedthe ontogenic phases of root formation using histological techniques and Scarecrow and Short‐Rootexpression quantification for RNA sequencing sample collection. We quantified the gene expres‐sions associated with root meristem formation, auxin biosynthesis, perception, signaling, conjuga‐tion, and cytokinin signaling in shoots harvested from 2‐ to 36‐month‐old plants. After IBA treat‐ment, 702 transcripts changed their expressions. Several were involved in hormone homeostasisand the signaling pathways that determine cell dedifferentiation, leading to root meristem for‐mation. In part, the age‐related decline in the rooting capacity is attributable to the increase in theARR1 gene expression, which negatively affects auxin homeostasis. The analysis of the tran‐scriptomic variation in the leaves and rooting zones provided profuse information: (1) To elucidatethe auxin metabolism; (2) to understand the hormonal and signaling processes involved; (3) to col‐lect data associated with their recalcitrance.