To advance understanding of the mechanistic factors regulating cassava
flowering, the leaf transcriptomes at 1) two stages of plant development
were compared in two genotypes at Ubiaja and Ibadan, Nigeria; and 2) three
controlled-environment growth chambers. For the first data set, three biological replicates were analyzed
for two locations, two genotypes, and two stages of plant development.
Field experiments were conducted from June 2017 to January 2018 at two
field stations in Nigeria: Ibadan (7.4° N and 3.9°E, 230 m asl) in Oyo
State and Ubiaja (6.6° N and 6.4° E, 221 m asl) in Edo State. At each
location the land was tilled and ridged with no extra nutrients or soil
amendments added. Fields were kept free of weeds with hand weeding.
Cassava stem cuttings of similar lengths (about 20 cm each), were planted
simultaneously in June 17, 2017 at both locations. For the second data set
in controlled-environment growth chambers, three biological replicates
were analyzed for three temperatures, three genotypes, and two stages of
plant development. Plants were grown in three growth chambers set at
22°C/18°C, 28°C/24°C, and 34°C/30°C, day/ night temperatures,
respectively. Photoperiod was held constant at 12 h light and 12 h dark.
Growth chambers were Conviron Controlled Environments, Ltd (Winnipeg,
Manitoba, Canada) model PGW 36 walk-in growth rooms (135 X 245 X 180 cm
[ht.]) with ten 400 W high pressure sodium and ten 400 W metal halide
lamps providing about 600 μmol photons (400-700 nm) m-2 s-1 at 1 m above
the soil surface. RNA extraction: In brief (see
published paper for details): total RNA was extracted from each sample by
a modified CTAB protocol. Samples were ground to a fine powder in a mortar
and pestle chilled with liquid N2; chloroform was added, mixed,
centrifuged and the top layer was used. Samples were purified on silica
RNA columns and eluted with RNAase-free water. 3 ́RNA-seq libraries were
prepared at the Cornell Genomics facility using the Lexogen QuantSeq
3’ mRNA-Seq Library Prep Kit FWD. See published paper for details. The
libraries were quantified with the intercalating dye QuantiFluor, evenly
pooled sequenced on one lane of an Illumina NextSeq500 sequencer,
single-end 1x86bp de-multiplexed based upon six base i7 indices using
Illumina bcl2fastq2 software (version 2.18; Illumina, Inc., San Diego,
CA). Illumina adapters were removed from the de-multiplexed fastq files
using Trimmomatic (version 0.36; Bolger et al. 2014). Poly-A tails and
poly-G stretches of at least 10 bases in length were then removed keeping
reads at least 18 bases in length after trimming The trimmed reads were
aligned to the Manihot esculenta genome assembly 520_v6
(
genome.jgi.doe.gov) using the STAR aligner (version 2.7.0f;
(Dobin et al., 2012)). Matrix table with raw gene counts for every gene
and every sample. Metadata are provided in the uploaded file.