SRX19302767 GSM7030371_r1 SRP421340 PRJNA932292 SRS16702802 GSM7030371 GSM7030371 RNA-Seq TRANSCRIPTOMIC cDNA Lettuce roots from each treatment (PS, PS+CH) were sampled at 72 hpt. Five biological replicates per treatment/timepoint combination were randomly selected. The soil on the roots was washed off and roots were pooled, flash frozen in liquid nitrogen and stored at -80°C before further processing. Total RNA was extracted using the CTAB method as described in detail by Luypaert et al. (2017). Contaminating DNA was removed using DNA-free DNA removal kit (AM1906, Invitrogen; Thermo Fisher Scientific, Inc., Waltham, USA, Massachusetts) according to the manufacturer's protocol. To study the overall transcriptional reprogramming in lettuce upon chitin treatment, in total five RNA samples per treatment sampled at 72 hpt were shipped to BGI Tech Solutions Co. Ltd. (Hong Kong, China) for cDNA synthesis, library preparation, and sequencing. DNBSEQ-G400 SRX19302768 GSM7030372_r1 SRP421340 PRJNA932292 SRS16702803 GSM7030372 GSM7030372 RNA-Seq TRANSCRIPTOMIC cDNA Lettuce roots from each treatment (PS, PS+CH) were sampled at 72 hpt. Five biological replicates per treatment/timepoint combination were randomly selected. The soil on the roots was washed off and roots were pooled, flash frozen in liquid nitrogen and stored at -80°C before further processing. Total RNA was extracted using the CTAB method as described in detail by Luypaert et al. (2017). Contaminating DNA was removed using DNA-free DNA removal kit (AM1906, Invitrogen; Thermo Fisher Scientific, Inc., Waltham, USA, Massachusetts) according to the manufacturer's protocol. To study the overall transcriptional reprogramming in lettuce upon chitin treatment, in total five RNA samples per treatment sampled at 72 hpt were shipped to BGI Tech Solutions Co. Ltd. (Hong Kong, China) for cDNA synthesis, library preparation, and sequencing. DNBSEQ-G400 SRX19302769 GSM7030373_r1 SRP421340 PRJNA932292 SRS16702804 GSM7030373 GSM7030373 RNA-Seq TRANSCRIPTOMIC cDNA Lettuce roots from each treatment (PS, PS+CH) were sampled at 72 hpt. Five biological replicates per treatment/timepoint combination were randomly selected. The soil on the roots was washed off and roots were pooled, flash frozen in liquid nitrogen and stored at -80°C before further processing. Total RNA was extracted using the CTAB method as described in detail by Luypaert et al. (2017). Contaminating DNA was removed using DNA-free DNA removal kit (AM1906, Invitrogen; Thermo Fisher Scientific, Inc., Waltham, USA, Massachusetts) according to the manufacturer's protocol. To study the overall transcriptional reprogramming in lettuce upon chitin treatment, in total five RNA samples per treatment sampled at 72 hpt were shipped to BGI Tech Solutions Co. Ltd. (Hong Kong, China) for cDNA synthesis, library preparation, and sequencing. DNBSEQ-G400 SRX19302770 GSM7030374_r1 SRP421340 PRJNA932292 SRS16702805 GSM7030374 GSM7030374 RNA-Seq TRANSCRIPTOMIC cDNA Lettuce roots from each treatment (PS, PS+CH) were sampled at 72 hpt. Five biological replicates per treatment/timepoint combination were randomly selected. The soil on the roots was washed off and roots were pooled, flash frozen in liquid nitrogen and stored at -80°C before further processing. Total RNA was extracted using the CTAB method as described in detail by Luypaert et al. (2017). Contaminating DNA was removed using DNA-free DNA removal kit (AM1906, Invitrogen; Thermo Fisher Scientific, Inc., Waltham, USA, Massachusetts) according to the manufacturer's protocol. To study the overall transcriptional reprogramming in lettuce upon chitin treatment, in total five RNA samples per treatment sampled at 72 hpt were shipped to BGI Tech Solutions Co. Ltd. (Hong Kong, China) for cDNA synthesis, library preparation, and sequencing. DNBSEQ-G400 SRX19302771 GSM7030375_r1 SRP421340 PRJNA932292 SRS16702806 GSM7030375 GSM7030375 RNA-Seq TRANSCRIPTOMIC cDNA Lettuce roots from each treatment (PS, PS+CH) were sampled at 72 hpt. Five biological replicates per treatment/timepoint combination were randomly selected. The soil on the roots was washed off and roots were pooled, flash frozen in liquid nitrogen and stored at -80°C before further processing. Total RNA was extracted using the CTAB method as described in detail by Luypaert et al. (2017). Contaminating DNA was removed using DNA-free DNA removal kit (AM1906, Invitrogen; Thermo Fisher Scientific, Inc., Waltham, USA, Massachusetts) according to the manufacturer's protocol. To study the overall transcriptional reprogramming in lettuce upon chitin treatment, in total five RNA samples per treatment sampled at 72 hpt were shipped to BGI Tech Solutions Co. Ltd. (Hong Kong, China) for cDNA synthesis, library preparation, and sequencing. DNBSEQ-G400 SRX19302772 GSM7030376_r1 SRP421340 PRJNA932292 SRS16702807 GSM7030376 GSM7030376 RNA-Seq TRANSCRIPTOMIC cDNA Lettuce roots from each treatment (PS, PS+CH) were sampled at 72 hpt. Five biological replicates per treatment/timepoint combination were randomly selected. The soil on the roots was washed off and roots were pooled, flash frozen in liquid nitrogen and stored at -80°C before further processing. Total RNA was extracted using the CTAB method as described in detail by Luypaert et al. (2017). Contaminating DNA was removed using DNA-free DNA removal kit (AM1906, Invitrogen; Thermo Fisher Scientific, Inc., Waltham, USA, Massachusetts) according to the manufacturer's protocol. To study the overall transcriptional reprogramming in lettuce upon chitin treatment, in total five RNA samples per treatment sampled at 72 hpt were shipped to BGI Tech Solutions Co. Ltd. (Hong Kong, China) for cDNA synthesis, library preparation, and sequencing. DNBSEQ-G400 SRX19302773 GSM7030377_r1 SRP421340 PRJNA932292 SRS16702808 GSM7030377 GSM7030377 RNA-Seq TRANSCRIPTOMIC cDNA Lettuce roots from each treatment (PS, PS+CH) were sampled at 72 hpt. Five biological replicates per treatment/timepoint combination were randomly selected. The soil on the roots was washed off and roots were pooled, flash frozen in liquid nitrogen and stored at -80°C before further processing. Total RNA was extracted using the CTAB method as described in detail by Luypaert et al. (2017). Contaminating DNA was removed using DNA-free DNA removal kit (AM1906, Invitrogen; Thermo Fisher Scientific, Inc., Waltham, USA, Massachusetts) according to the manufacturer's protocol. To study the overall transcriptional reprogramming in lettuce upon chitin treatment, in total five RNA samples per treatment sampled at 72 hpt were shipped to BGI Tech Solutions Co. Ltd. (Hong Kong, China) for cDNA synthesis, library preparation, and sequencing. DNBSEQ-G400 SRX19302774 GSM7030378_r1 SRP421340 PRJNA932292 SRS16702809 GSM7030378 GSM7030378 RNA-Seq TRANSCRIPTOMIC cDNA Lettuce roots from each treatment (PS, PS+CH) were sampled at 72 hpt. Five biological replicates per treatment/timepoint combination were randomly selected. The soil on the roots was washed off and roots were pooled, flash frozen in liquid nitrogen and stored at -80°C before further processing. Total RNA was extracted using the CTAB method as described in detail by Luypaert et al. (2017). Contaminating DNA was removed using DNA-free DNA removal kit (AM1906, Invitrogen; Thermo Fisher Scientific, Inc., Waltham, USA, Massachusetts) according to the manufacturer's protocol. To study the overall transcriptional reprogramming in lettuce upon chitin treatment, in total five RNA samples per treatment sampled at 72 hpt were shipped to BGI Tech Solutions Co. Ltd. (Hong Kong, China) for cDNA synthesis, library preparation, and sequencing. DNBSEQ-G400 SRX19302775 GSM7030379_r1 SRP421340 PRJNA932292 SRS16702810 GSM7030379 GSM7030379 RNA-Seq TRANSCRIPTOMIC cDNA Lettuce roots from each treatment (PS, PS+CH) were sampled at 72 hpt. Five biological replicates per treatment/timepoint combination were randomly selected. The soil on the roots was washed off and roots were pooled, flash frozen in liquid nitrogen and stored at -80°C before further processing. Total RNA was extracted using the CTAB method as described in detail by Luypaert et al. (2017). Contaminating DNA was removed using DNA-free DNA removal kit (AM1906, Invitrogen; Thermo Fisher Scientific, Inc., Waltham, USA, Massachusetts) according to the manufacturer's protocol. To study the overall transcriptional reprogramming in lettuce upon chitin treatment, in total five RNA samples per treatment sampled at 72 hpt were shipped to BGI Tech Solutions Co. Ltd. (Hong Kong, China) for cDNA synthesis, library preparation, and sequencing. DNBSEQ-G400 SRX19302776 GSM7030380_r1 SRP421340 PRJNA932292 SRS16702811 GSM7030380 GSM7030380 RNA-Seq TRANSCRIPTOMIC cDNA Lettuce roots from each treatment (PS, PS+CH) were sampled at 72 hpt. Five biological replicates per treatment/timepoint combination were randomly selected. The soil on the roots was washed off and roots were pooled, flash frozen in liquid nitrogen and stored at -80°C before further processing. Total RNA was extracted using the CTAB method as described in detail by Luypaert et al. (2017). Contaminating DNA was removed using DNA-free DNA removal kit (AM1906, Invitrogen; Thermo Fisher Scientific, Inc., Waltham, USA, Massachusetts) according to the manufacturer's protocol. To study the overall transcriptional reprogramming in lettuce upon chitin treatment, in total five RNA samples per treatment sampled at 72 hpt were shipped to BGI Tech Solutions Co. Ltd. (Hong Kong, China) for cDNA synthesis, library preparation, and sequencing. DNBSEQ-G400