Validation of Novel Reference Genes for Reverse Transcription Quantitative Real-Time PCR in Drought-Stressed Sugarcane

Table 5

Potential reference gene combinations (and number of genes involved in each comparison) used in gene expression normalization of glutamine-dependent asparagine synthetase (AS), with cDNAs of sugarcane accessions (root under drought stress, 24 h of continuous dehydration).

Comparison	Gene combinations	Number of genes	Expression* value	𝑃 value	Regulation
1	𝛼TUB, H1, and SAMDC	3	1.431	0.112	ns
2	GAPDH, 25S rRNA, and SAMDC	3	1.482	0.009	ns
3	𝛼TUB, H1, GAPDH, 25S rRNA, and SAMDC	5	1.496	0.113	ns
4	𝛼TUB, H1, UBQ, and SAMDC	4	1.557	0.105	ns
5	UBQ and SAMDC	2	1.595	0.305	ns
6	𝛼TUB and H1	2	1.519	0.000	UR
7	GAPDH and 25S rRNA	2	1.600	0.017	UR
8	𝛼TUB, H1, GAPDH, and 25S rRNA	4	1.559	0.011	UR
9	𝛼TUB, H1, and UBQ	3	1.667	0.033	UR
10	GAPDH, 25S rRNA, and UBQ	3	1.725	0.017	UR
11	𝛼TUB, H1, GAPDH, 25S rRNA, and UBQ	5	1.640	0.017	UR

∗REST software analysis after the ΔΔCq method. UR: upregulated; ns: not significant at 𝑃<0.05; 𝛼TUB: alpha-tubulin; H1: histone H1; SAMDC: S-adenosylmethionine decarboxylase; GAPDH: glyceraldehyde 3 phosphate dehydrogenase; 25S rRNA: 25S ribosomal RNA; UBQ: ubiquitin.