Table 2.
ER-stress response genes are induced by heat in pollen (A) and in PTs grown at basal temperature (B)
| A. Genes Up by Heat |
B. Genes Up in Pol Tube |
C. Heat | ||||||
|---|---|---|---|---|---|---|---|---|
| Total Genes | Pol1 | Pol2 | Pol2 | Wang | Qin | Qin | Leaf and Shoot | |
| Function/Protein Class | RNA1 | RNA2 | RPF2 | PT/MP | PT/dry | SIV/dry | ||
|
| ||||||||
| Number of Genes Induced | ||||||||
| ER Chaperone | ||||||||
| BIP, CNX, CRT, and ERDJ | 11 | 10 | 11 | 11 | 7 | 0 | 10 | 8 |
| ER/Golgi Traffick | ||||||||
| p24delta#, ERD2 | 10 | 6 | 7 | 7 | 4 | 0 | 7 | 1 |
| ER Isomerase | ||||||||
| PDIL, ERO1 | 6 | 3 | 5 | 5 | 3 | 0 | 5 | 2 |
| ER-associated degradation | ||||||||
| DER, Hrd1B, and CDC48B | 5 | 5 | 5 | 4 | 2 | 1 | 4 | 3 |
| Transporter UDP-Gal UTr1 to UTr3 | 3 | 2 | 2 | 2 | 2 | 0 | 2 | 2 |
| Glycosylation-related GPT, UGGT, and TIN1 | 3 | 2 | 2 | 2 | 0 | 0 | 1 | 1 |
“Total genes” indicates the number of differentially expressed genes in each protein class from six experiments. Number of genes induced refers to members of each class that show a significant increase (log2FC > 1) of RNA transcripts in response to heat stress (A and C) or PT germination (B). Examples of genes for each class are abbreviated. Gene identification numbers and log2FC values are provided in Supplemental Table S2.
(A) Genes upregulated by heat. Pol1 and Pol2 refer to transcriptome data of Rahmati Ishka et al. (2018) and Poidevin et al. (2020) from A. thaliana, respectively. Heat stress regimes for Pol1 and Pol2 pollen are described in Figure 1, and transcript levels determined using RNA-seq. “RPF” refers to ribosomal protection fragment, a measure of mRNA undergoing translation. See Supplemental Table S2 for gene descriptions and the fold increase in transcript (log2FC) for each gene.
(B) Induction of transcripts during PT germination and growth at basal temperature. Wang et al. (2008) tested expression in PTs (4 h) grown in vitro relative to MP. Qin et al. (2009) tested expression in PTs grown in vitro (PT, 4 h) or SIV relative to dry (ungerminated) pollen. Variation in transcript accumulation in PT may be caused by different experimental conditions and dehydration state of MP and dry pollen.
(C) Induction by heat stress in leaves and shoots. Average value from two experiments is shown (Kilian et al., 2007; Sugio et al., 2009).