The northern root-knot nematode ( Meloidogyne hapla ) is a critical pathogen with a wide host range. Quantitative real-time polymerase chain reaction (qRT-PCR) has been used to elucidate gene expression and function of M . hapla . Suitable reference genes are required to ensure accurate results of qRT-PCR for normalising gene expression. Eleven candidate reference genes of M . hapla were selected to evaluate gene expression stability under different conditions. The stability of candidate reference genes was ranked using RefFinder analysis, and the optimal number of reference genes was recommended with geNorm. Notably, the most stable reference genes were SDHA , Mdh , and RpS6 for all samples; SDHA and RpS6 were particularly stable during development stage treatments, whereas Mdh and RpS6 were appropriate for temperature and inorganic compound treatments. In contrast, the least stable reference genes were Actin1 during development stages and all other treatments, GAPDH for temperature treatments, and α-Tub for inorganic compound treatments. One target gene, Mh-Hsp90 , was used to verify the selection of reference genes, results showed Mdh and RpS6 could be used as suitable reference genes for M . hapla , and Mdh plus RpS6 were better. Our finding contributes to further work on gene transcription analysis in M . hapla .

ABSTRACT. Quantitative reverse-transcription PCR (qRT-PCR)is a versatile technique for the analysis of gene expression. The selection of stable reference genes is essential for the application of this technique. Cauliflower (Brassica oleracea L. var. botrytis) is a commonly consumed vegetable that is rich in vitamin, calcium, and iron. Thus far, to our knowledge, there have been no reports on the validation of suitable reference genes for the data normalization of qRT-PCR in cauliflower. In the present study, we analyzed 12 candidate housekeeping genes in cauliflower subjected to different abiotic stresses, hormone treatment conditions, and accessions. geNorm and NormFinder algorithms were used to assess the expression stability of these genes. ACT2 and TIP41 were selected as suitable reference genes across all experimental samples in this study. When different accessions were compared, ACT2 and UNK3 were found to be the most 2 X.G. Sheng et al. Genetics and Molecular Research 15 (3): gmr.15038348 suitable reference genes. In the hormone and abiotic stress treatments, ACT2, TIP41, and UNK2 were the most stably expressed. Our study also provided guidelines for selecting the best reference genes under various experimental conditions.