Transgenerational memory of gene expression changes induced by heavy metal stress in rice (Oryza sativa L.)

BMC Plant Biology

Table 2 Transgenerational alteration and inheritance of gene expression patterns in 8 randomly chosen S₁ plants derived from a Hg²⁺(50 μm . L⁻¹)-treated S₀ individual

Gene name	Alteration of gene expression pattern in the S₀ plant and its S₁ progenies									Type and Freq. (%) of pattern^a
	S₀-Hg²⁺	1	2	3	4	5	6	7	8	Inherit. of S₀ pat.	Rev. to mock Pat.	New pat. (Trans. memory/others)
Tos17A	U	i	+U	i	+U	i	i	+U	i	62.5	0.0	37.5 (37.5/0.0)
Tos17B	U	i	+U	+U	+U	+U	+U	+U	+U	12.5	0.0	87.5 (87.5/0.0)
Osr42	U	+U	+U	+U	+U	+U	+U	+U	+U	0.0	0.0	100.0 (100.0/0.0)
Homeobox gene	U	i	i	i	i	i	r	i	r	75.0	25.0	0.0 (0.0/0.0)
HSP70	U	r	i	i	i	i	i	i	i	87.5	12.5	0.0 (0.0/0.0)
YF25	D	i	i	r	r	r	-r	-r	-r	25.0	37.5	37.5 (0.0/37.5)
SNF-FZ14	U	i	i	+U	+U	+U	+U	+U	+U	25.0	0.0	75.0 (75.0/0.0)
OsHMA1	U	+U	+U	+U	+U	+U	+U	+U	+U	0.0	0.0	100.0 (100.0/0.0)
OsHMA2	U	i	D	D	i	D	i	D	i	50.0	0.0	50.0 (0.0/50.0)
OsHMA4	U	r	r	i	i	i	r	r	r	37.5	0.0	62.5 (0.0/62.5)
OsHMA5	U	i	i	r	+U	i	+U	r	i	50.0	25.0	25.0 (25.0/0.0)
OsHMA6	U	i	i	+U	+U	+U	+U	+U	+U	25.0	0.0	75.0 (75.0/0.0)
OsHMA7	U	i	+U	+U	+U	+U	+U	+U	+U	12.5	0.0	87.5 (87.5/0.0)
OsHMA8	U	i	i	i	i	+U	+U	+U	i	62.5	0.0	37.5 (37.5/0.0)
OsHMA9	U	i	i	i	i	i	i	i	i	100.0	0.0	0.0 (0.0/0.0)
Average Freq. (%)^a										41.7	6.7	41.7/10.0

Explanation of symbols: U = up-regulated gene expression in the S₀ plant;
+U denotes further up-regulated gene expression in the S₁ progeny plant;
D denotes down-regulated gene expression in the S₁ progeny plants compared to the mock control
i denotes inheritance of S₀ expression pattern in the S₁ progeny;
r denotes reversal to Mock control expression pattern in the S₁ progeny;
Note: ^a The average frequency of the specified pattern in S₁ progeny plants. For calculations the two copies of Tos17 were treated separately,
^aRelative band intensities were used to calculate the percent progeny following in either of the three gene expression categories: i) inheritance of Hg- treated S₀ pattern, ii) reversion to the mock pattern, and iii) a differential expression pattern (cf. Fig. 2)

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